It hasn't been my experience that it's useless. I've reported an issue with a game that got fixed even though it only had one thumb (mine). Another issue I reported on a different game got a small number of other thumbs (4 total) and was fixed. When people are considering making a bug report of their own, there's encouragement to check to see if the same thing has already been reported and just add a thumb (and perhaps an additional comment) there. I do that, and I assume others do too. In any case, the ulimate goal of a bug report is to get an issue fixed, not particularly to maximize thumbs and get top placement in the bug-report list, and I imagine developers are going to look at the entire list. Items with lots of thumbs might get bug-fix priority (and that seems reasonable), but I would be surprised if a report was entirely ignored forever because it had few thumbs. I think it would at least be considered (though it might be decided that no change would be made).