There's a quite a number of featured/daily snacks that is in book format and that pretty much why I started this thread cos it was too uncomfortably tiny to read when I click on it 
I guess I can always install Tap on my tablet if I care enough, but if it's an extra inconvenience for me to read one chapter of a daily snack, and I may not have my tablet when I'm out, I just quickly move on to other things on my phone (ie. webtoon or lezhin) and already forget about it by the time I got home
Usually a business (like Tap/webtoon/lezhin) are more aware to change that will hugely affect their future since there's alot in stake for them vs individual creator, that's why Lezhin and webtoon featured content (not discover section) only does mobile version.
As far as Tapastic premium content, I saw some variety on mobile vs book scrolling format and I usually just moved on from the book version since it's hard to get into it when it's all too cramped,
and the pay barrier makes it even easier to move onto something else since there is no shortage of content out there 