[robonerd]

Youtube comments are useless for both criticism (generally censored, either by the video creator or by youtube itself) and praise (virtually always vacuous.) The only thing they are good for is adding context or relevant anecdotes. E.g. a video about an engine may have comments from retired mechanics who've serviced that engine before.

It really depends on what kind of content you're watching though. For wide swaths of content on youtube, there is nothing worthwhile that can be said in the comment section, either because youtube wouldn't show that sort of comment, or because there's earnestly nothing to be said.