I believe they are definitely general purpose. You can browse the web, do professional work in several industries (spreadsheets for business, media editing programs, tax software, etc), play soke fairly intensive games, and track all kinds of parts of your life. And then you can dock all this to a monitor and use a KB&M and treat it like a ultrathin workstation.

I'm struggling to think of something you can't do on a phone/tablet these days. Dual monitor support seems to be beyond most devices I tried it with. Maybe some government applications for security purposes.