Actually there are programs that you could place tabs in vertical or horizontal split if you want to compare/copy-paste.
I tried the tab-instead-of-app paradigm, the biggest problem for me was the lack of consistency in different applications for new-tab, and tab navigation, and as soon as I open vim in a terminal it could get even more confusing. The other problem is that if some tab misbehaves I had to close all of them, which made me mad.