I have to disagree with some of these comments saying that greyscale is faster than color comics. Both of them can be fast or complex depending on which style you're going with. Personally, my first comic was done in greyscale (with selective coloring for the main characters) and it takes me 3-4 days to make a page. Though, if I don't want to sleep/eat/move from my computer I can crank out a greyscale page in one day--but it's no easy feat.I'm by no means a professional, and my art is turrible needing some improvements, but here's an example of one of my greyscale pages from my first comic.
I love color comics just as much as the next person, but I also enjoy greyscale comics simultaneously. If an artist is unsure of whether to make their comic greyscale or color, I would suggest doing some experimental test pages to see which one flows right for the story you're trying to convey and which one you prefer. Due to some experimentation and because of the story/visuals I'm trying to portray in my 2nd comic series, I decided to go with color pages; but this is just kinda for my own benefit and not to anyone else.
Though there are more color comics, I believe as long as it's a compelling story, it doesn't matter on the artstyle. For example, the animated movie "It's a Beautiful Day" is completely drawn in stick figures. But while watching it, I didn't care about the artstyle because I was so engrossed with the story and the characters. Let me tell you, it was a really heavy story, ended bittersweet, and I respected the artist all the more that they told such a serious-toned story with stick figures.
So that's my opinion on the whole matter. Both styles require equal respect and it's ultimately up to the artist and don't be afraid to experiment. Do what you want since it's your creation, don't give into the fandom that "color comics are more popular" or whichever. I apologize in advance if I offended anyone with my opinion in this ^^; I didn't mean to dampen anyone's day <3