Ummmm...............
I thought it was clear that "I" was the main protagonist, as it were, no one else - and surely you meant to say that because
I couldn't see a good reason for a feature, does not mean that
others can't see a good reason...? [ There being no absolute good reason implied by my comments.]
Again, I don't keep many books on my hard drive - one of the bonus points of the reader is that, by and large, I don't have the [problem of bookshelves/hard drives/etc. filling up with books so there's no room for any more - but, 2,500 even I would think was fine to go travelling with.
And of course it's easier to d/load directly onto your device after using said device to find a book, than not - I just have sufficient minutes spare at some point in some day not to be bothered with about it - especially as I have such a reader than pleases me aesthetically, quite apart from it's function. [ which I found was enhanced by not having to faff around with a tiny keyboard, quite a plus for anyone with a damaged digit . The expanded memory facility came as a nice bonus, making me happier when I realised just how useful it would be for the way I like to read.]
I had obviously managed to think of those 3 reasons for wifi and dismiss them.
Nothing's perfect for everyone, is it ....................