It would make Steemit life hell for newbies. Comments are there to stay on authors' posts and their replies tab. They can see them and reply to them. And they can upvote them to bring more valuable comments at the top for more visibility. I support upvotes on comments. I think it is a wonderful way of ensuring healthy interaction.
Just my opinion and it's great to look at things differently.
Yes, I totally agree,,, upvoting comments is good,,, i'm just don't think the "curration" rewards (going back to the upvoter as opposed to the commenter or author) are serving the system.