I had the same feeling about iCloud before I had a Mac and just a iPhone, but now that I have a Mac and that there are features such as “Sign-in with Apple” and “Hide My Email”, I can’t imagine living without. Apple Books is also a great eReader for PDFs and ePubs on macOS and iPad/iPhone which provides syncing across all devices. Not just the books themselves but also the chapters you’re at, bookmarks, notes, etc.
I suggest revisiting and if it’s not for you, that’s fine. But otherwise, yeah never sign-in with Apple.
At least they are not agressive about it, unlike Windows 10 or even 11 home which doesn’t even allow local accounts.
Apple Books also syncs position in your own epubs, unlike my new Kobo Sage which’ll only sync reading position in books you’ve bought from Kobo. I still love my Kobo Sage and feel like managing my library with Calibre is better than Apple Books. But the iCloud syncing experience with Apple Books is clearly superior. People give Apple a lot of shit for their built in apps not being great (which is a good argument against them having a monopoly on iOS) but at least they nailed Books syncing.
Apple Books sends what you're reading, and how often, and when (and approximately where, via client geoip) along with your unchangeable device hardware serial number to Apple.
Remember when librarians basically revolted because the patriot act let the feds get library borrowing records without a warrant? Apple's Books app is several times worse. It's nonconsensual
spyware, even if you use only your own local files and never engage in trade with Apple for ebooks.
iCloud enables the (effectively unencrypted) iCloud Backup automatically on iOS, which sends a complete effectively unencrypted copy of almost everything on your device to Apple every night when charging.
Apple can decrypt the entire thing without you, your password, or your device. They do this when they receive a warrant, and they do this 20,000+ times a year for warrantless requests (no probable cause) from
the USG, too. This includes all your photos (effectively unencrypted) and all your iMessages and attachments. Nothing really important on your iPhone is private from Apple.
Also, if your cc fails for whatever reason, you will get locked out of your Apple ID, and won't be able to log in to or use any of the services you use Sign in with Apple on.
I suggest revisiting and if it’s not for you, that’s fine. But otherwise, yeah never sign-in with Apple.
At least they are not agressive about it, unlike Windows 10 or even 11 home which doesn’t even allow local accounts.