Don't throw away your Kindle, Jailbreak it and take back ownership. Make your Kindle even better with KoReader and other apps. If you wanna see whats possible i recomment this Yt video. If you wanna get started here are all instructions: https://kindlemodding.org/ Don't let it scare you it seems complicated but its just a lot of (easy) steps. So definitely possible in <2h.
I decided to give it a shot not too long ago. Its a bit of give and take. Pros and cons.
With KOreader you get more options for customizing layouts and fonts and spacing. You can also just put books in different folders which is great for organizing. Like I have a folder for my horror, fantasy, gen lit, classics. While I made sure to organjze my stuff on Caliber, theres not as many options on Kindle out the box, so I cant just look through books based on that, which is a feature I always wished they would have added. It also read more formats. Epub is seen as the universal one for books, but it also does PDF, DjVu, FB2, PDB, TXT, ZIP, CBT, CBZ, FB2, RTF, HTML, CHM, and DOC.
But also, yeah. My Kindle is usually on airplane mode anyways because wifi drains the battery, and I just pulled things over with the computer anyways. The UI while scrolling through books also looks so much nicer IMO. And as long as youre not doing hundreds of books at a time, its not that hard to set up collections. And while the Kindle doesnt have quite as many in depth options for fonts and shit, the specific file format for the specific UI for the specific devices also meant I never had issues with getting it to look nice.
So over all, if you like tinkering with stuff, its cool. But I do agree that it's not really needed. You can still download books from other sources and then just transfer them over.