The good thing about it is you dont need line of site.
That has to be a bug. Even though there's no attack roll, I'm pretty sure you should not be able to cast it on someone you can't see at all because there's a solid wall between you and them.
It's pretty trash even in pen-and-paper D&D 5e.
I've watched a lot of Critical Role, and yeah, it's generally used as the "I have nothing better to do option", and even then it's rarely effective.