Oh my. I almost always comment on the voting thread.
I always assumed people wanted to hear critiques, regardless of where they are posted. While comments on the voting thread may be "too late" to help someone improve a piece and win, it's the most convenient place to round up one's thoughts about the entries. In fact, I get annoyed when there are no comments, because I like to know how I
failed to capture the viewer, or how my piece is inferior to others.
And if comments influence someone else's vote, isn't that important too? If an art noob comes in and votes based on his under-developed artistic sensibilities, how is that more virtuous than teaching him something about how to look at art? By allowing comments, not only does the artist get valuable feedback, but so do the voters. Disallowing comments at voting time has the effect of excusing mistakes by not calling them out, and of rewarding inferior art by allowing it to succeed due to lack of viewer understanding. To that I say Boo hiss.
For me, the bottom line is always learning how to be a better artist. Restricting comments does not serve that end.
Nick AvalloneAngryFungus Art Blog