It doesn't save you any money if you've already paid for it.
I was more getting at "torrent and not worry about binging the entire series within 3 weeks," but you do you I guess?
AHHHHHH FUCK, I FORGOT ABOUT COMIXOLOGY 
The problem for me is Kindle. I know there's (forgetting the name off the top of my head) that converts eBooks to/from Kindle but that's just a complete hassle. Then again, I have a bunch of Humble Bundle books (like Chuck Tingle.
) I need to get through and could probably put them on my Google account to read through Google Books, but the Android Google Books app plain sucks (or the Doom Engine Black Box book just sucks digitally) for mobile.
The Kindle browser, Windows, and Android app are all solid for reading.
AFAIK, most tech books like CompTIA textbooks from Michael Meyers aren't on there/Google either.
I hate all Amazon software. I don't think there's a single product they've created that fits my standards of "well designed," outside of some Kindle (e-book, not Fire tablet garbage) hardware models. I hated the Amazon website for reading Kindle books, and I hated the Android app almost as much.
Play Books on Android is OK, the Material Design 2 redesign looks nice but I'm totally unfamiliar with the Kindle app these days so I can't speak to feature parity.
The Play Books website is bad, but the entire Play site is bad and that's kinda caught up in it. Despite featuring a really bad 2013-era design still, they actually started adding new features to the site in the last year (after like 6 years of no updates), so there's hope there.
I bought a Kindle about 4 years ago but I knew back then I didn't want to get sucked into the Amazon content ecosystem (this was back when they were refusing to support Chromecast, and I didn't expect Google and Amazon to get along better in the future.) So I used Calibre to transfer my ebooks from Play Books. Once you get it setup, it's not too bad. You literally launch Calibre, it'll detect any new ebooks in folders you've specified, and in one or two clicks you can batch-convert+send them to your Kindle, either plugged in or "wirelessly" to the Kindle-specific email address you have. Setting it up is kind of a pain though (involved creating a developer token, and installing Adobe Digital Editions), and I've only gone Play Books -> Kindle, and not the reverse.
This all said, yeah, like I just realized I have a fuckton of shit on Comixology. I always wanted to keep my comics collection in the same place.
Why the fuck did you have to sellout, Comixology. :'( Play Books did a big hullabaloo about launching "full" comics support a few years back, but it still trails Comixology I think... guess I just have to suck it up and go with Play Books... whenever DC pulls their heads out of their asses and they fire Bendis.
I guess I could cancel my Twitch accounts too...
And I never used AWS or Prime Video.
marathon all of Star Trek before your Prime expires, since they have everything in glorious HD versions (where available) 
What's the Netflix situation these days?
I only own the Hawkeye/Matt Fraction run on Kindle there, so it's not too big a deal if I can convert it. I know I have like 2-3 cook-books that I'd have to convert (but I also have a few others via Humble so it wouldn't be a big deal).
I'm not talking software, per se. But Kindle's app makes reading eBooks a lot easier on the eyes than Google Play Books.
The only reason I know this is because Doom Engine Black book (again) is exclusive there. His Wolf3D engine book was on Kindle but I guess he got more sales on Google or something so he went there for that one:
https://play.google.com/store/books/details/Fabien_Sanglard_Game_Engine_Black_Book_DOOM_v1_1?id=wel6DwAAQBAJ <---You can use the "free sample" [IIRC] to see what I'm talking about. That said:
Google Play web-browser reader [HUGE,1080
]

Seems ok. Though it doesn't let me "black out" the background for eye-strain/easier reading like Kindle.
But anyway, GPB Android:

It isn't "formatted" for phones. I dunno if it's just this book, but reading my (pirated :shhh ) copy of Cyberpunk 2020 or RED rulebook off my Google Drive runs into the same "pain in the ass to read on mobile" issue but I blamed that on the Drive app, not the Book's app which should format things easier.
Compare to Kindle (not the same book, obviously):

It's night and day in regards to how much easier on a 7inch or so screen reading books via Kindle is compared to the "having to pinch and zoom every fucking page" Google Play Books is.
I'd take screen shots of the Windows app to show my "black background, white text" option which looking at the browser and phone option of GPB... doesn't have. Whereas on Kindle they do.
I know you can load .pdf's into the Kindle app, but you're still using Amazon at that point so a "boycott" like you want to do is a little... harder for me in terms of reading-ease/use/preference choices for eBooks.
Edit: IIRC, I have shoved a few .pdf Humble Bundles through the Kindle app on Android and it worked fine so it MIGHT come down to how the eBooks are formatted/etc. so IDK. I just know buying books off Amazon is a much easier on the eyes/user experience-experience than GPB.
spoiler (click to show/hide)
That said, I've been buying TV shows I like off Google since they let me download to watch offline at my own pace. Something Amazon doesn't fucking do and neither did iTunes (beyond iPod/iPhones. *sigh*)