It's a pretty easy question to answer: Yes, they do. Look at the engagement in terms of likes and replies on almost any video. Clearly people are reading and participating.

That's exactly what I was thinking. I'll sometimes skim comments during a boring bit in a video (such as an old-school NES/SNES speedrun), but I don't attempt nor expect serious discussion or rebuttals. I imagine the noise-to-signal ratio is even worse for videos with any type of political content.

I sometimes read them, especially on my own channel. Surprisingly, I haven't really encountered too much in the way of political idiocy there, perhaps because I don't tend to make videos about politics/anything that could get an ideological reaction.

So if a channel is fairly obscure and doesn't focus on politics, the comments can be... bearable.

But anything remotely popular is a hive of scum and idiocy that most people will rightfully not touch with a fifty foot bargepole. Less political there just means more 12 year olds posting outdated memes in place of the Russian bot farms and political trolls.

I only look at the first 5 comments, incase the youtuber responds to them or likes them directly. Everything else is just repetitive low quality spam usually

They are not available on TV (Smart TV, Fire Stick, PS4...) which is used more and more. So I guess, fortunately, they are not that important to Google

I read them more for entertainment than any other reason. Just to see what's out there.

When I watch youtube videos of a technical nature, there tends to be much higher-quality comments.

I get a chuckle out of them sometimes.