On the web, today, commenting on users is essential. "The Wall" on facebook is a web phenomenon and it's become a crucial part of what's expected on a community driven site.
Bio has taken a good step forward in allowing us to create user profiles as nodes...however, I would argue that the only reason that bio module is usable (more so than nodeprofile, etc) is that it seamlessly takes over core's user profile screen...allowing you to function very cleanly within the drupal user system.
The problem is...the core /user pages aren't nodes themselves, therefore they don't allow you to print the $links variable...thereby not allowing comments on bio nodes (ie users) when they take over the /user pages.
Talking with jjeff on irc, way back when, he was aware of this, and you'll see that in the new version of bio $links have been purposely removed.
This post is a call to somehow make comments/$links available on the /user pages which bio takes over. Bio node is extremely powerful because it makes profiles nodes and allows you to take over the user profile pages...but if you want comments, you can't use both of these awesome features.
I'd say getting this to work would be a huge improvement for bio.