I really love this thread aaaaa I've found a few comics to follow, and of course there are a few of my favs already in here...
I personally like greyscale comics both because I enjoy the aesthetic and for the time invested.
I grew up reading manga like a lot of people here, and I think that the grey-tones vs color lends itself to creativity and imagining the colors while you read it, it feels closer to a novel than to a movie, to me? If color is used in a comic, I prefer when it's done for mood and more abstract than just denoting the local color of objects only.
When I color a comic, it takes almost as much time as all other steps combined (sketching, inking, etc) so it's just... a slogggg. I don't know if I could ever do it for a longform comic of my own. I used to work as a colorist for one of the runs on DC comics' online service before it went defunct, and I enjoy coloring when it's the only task I have to do and can focus on it. It really is its own beast and mindset to me, I can't do both when working on a long series.
That being said here's a page from the comic I do the art on: