When to use UserComments rather than Comment class?

Hi,
I'm looking into comments&microdata. I read the whole UserComments vs
Comment discussion from 2012. It is said there that
http://schema.org/Comment encodes the creative work by someone while
http://schema.org/UserComments encodes the action event of doing a comment.
Can anyone give me a real world example of when I would want to use
UserComments rather than Comment? Also the Article#comment property
(according to schema.org) refers to UserComments rather than Comment which
seems weird. Can I just specify the itemtype as Comment and use
CreativeWork(/Comment) itemprops instead?

Cheers,
Martin