Sorry, got the impression you were asking why folks might want it. I see now it was a specific question for OP.
But given that you responded. It is webmail, it is not great but it does allow me to read and respond to a large chunk of my email from just about anywhere, when abroad.
It does hold thousands of books, but even then I cannot pre-empt the books i might want or the information on which I need to read up. Often reading one book triggers another that i might want to, or need to read. so downloading on-demand works very well for me. WiFi can be a procedural pain sometimes, but also it is not ubiquitous. You don’t get Wifi everywhere, not on a boat, not with a goat, not in the rain, not on a train.
if you’re looking at it going “hey, free web browser” you’re likely to be disappointed.
Perhaps, I couldn’t really say, but if you’re looking at it going “hey, free bananas and custard” you’re also likely to be disappointed.
I don’t mean to be contrary, just that it is very useful if you travel much. Admittedly if I went to from my home to the same place of work every single day. Spending most of my life in either one of the two places, save for the odd holiday here and there, then I probably wouldn’t see much use for it either, though I’d hope to have enough about me to see a world beyond, in which it might be useful.