Not until there's a true "killer app" for reading on the mini—and no, Apple Books isn't it unless you're fully committed to buying all your books from Apple and living with it as a clunky manager for your existing books.
It's a beautiful app for actually reading, though. I wish I could use it as my primary book app. But in my experience, it's frustrating when organizing, searching, or managing metadata beyond "Title" and "Author". Worse, when the iPad is running low on storage, it can remove downloaded books—even the ones you've manually downloaded recently. That was an unpleasant surprise on my last cruise.
Unfortunately, the third-party landscape isn't much better. Yomu is decent, but I often run into formatting glitches, even with simple novels. KyBook is pretty much abandonware at this point. RIP Marvin. BookFusion is okay, but feels like it's trying to do too much (and is yet another SaaS subscription). And the big-name competitors are too deep in their own ecosystems of bookstores (Amazon, Barnes & Noble, etc.) with weak support for existing e-book libraries, just like Apple.
There's some promising stuff on the horizon like BookNexus (still in beta) but it seems like this category of apps is stagnant. That's a shame, because an OLED iPad mini could definitely be a great reading device for a lot of people. OLED isn't perfect, but for technical manuals, diagrams, magazines, maybe you're into graphic novels/comics—there are reasons to look beyond e-ink.
I just wish Apple would invest in the Books app to really make the iPad shine as a reading device. That's why the Kindle still owns this space. It isn't just the e-ink display; it's the whole system. Amazon took the iPod + iTunes model and built it for books. Apple could absolutely do the same, but the Books app is only halfway there.
