Comments are essential. Writing good comments is as skilled a task as writing the code.
(as an aside; the most important comment is WHO. Because knowing who wrote/modified a block of code is ridiculously useful for all sorts of obvious reasons)
Blame is useful in more elaborate context but... comments are instant :) And that is important.
1) Changing version control systems may be an unwinnable corporate political battle, while changing comment style may just be a team decision.
2) Not everyone who may need to understand or modify your code may have access to your repositories. I worked on a program where partner companies were provided source snapshots for developing their own algorithms but were not allowed access to our repositories.
IME, the only use it usually has on its own is knowing which people that are no longer on the team to blame to blame for the poor state of the code (both the operational parts, and the absence of useful code comments on the intent or rationale for the current code structure.)
WHO is not the most important comment (though its probably the most universally necessary part of a comment -- a need for a who comment always implies the need for some other comment, and most other comments should include a who.)
The only reason I've ever had for knowing who wrote code is if the code+comments+tests do not adequately explain what's going on and I need to know. On most of those occasions the person who wrote the original code had already left the organisation.