I don't know if this is a question of effective or not. Both can be.
When I think of my favourite comics, half or more are grayscale, the other half colour. I love the stark contrast and tonality of grayscale pages, but some authors have such cool colour palettes and moods with their pages I can't help but be drawn to them as well. Seeing comics in black and white is relaxing, even though I grew up reading both. Coloured comic pages can distract me and are too busy, oftentimes, especially in super hero comics. Someone who reads them a lot though probably wouldn't have that problem and wouldn't have the headache! Think about your audience.
Question: Do you ENJOY working in colour? Is it natural?
Some thoughts:
In essence, you can do pretty much the same thing with either B/W (or grayscale) or colour, but the approaches are different. There are many people on this thread who like one over the other, and who think one is harder than the other. This is very subjective! So in short, do what you like to do and what suits you.
Longer version? Here.
Whether or not you do colour or black and white does not have to effect the amount of detail in your comic. Mine is highly detailed, grayscale, and has a lot of tone variation. (I also do not use screen-tones.) I chose grayscale because I like the look. Doing pages in colour adds about an hour or more for me, but were I to be used to it I bet that would go down.
You can do mood and atmosphere with either; you just have to learn its tricks. For grayscale, you will need a solid grasp of value, balance, and contrast to get there. Keep in mind that there are a lot of tools in comics such as panel flow, readability, etc that add to mood, atmosphere, storytelling, etc. Colour or B/W is simply another layer to that.
If you do strictly black and white, test out some shading methods like hatching and cross-hatching. A lot of B/W comics have no screen-tone. You could play with line variation, deep shadows, etc. I feel this look is pretty crisp when you have a proper balance.
High contrast and balance will help your grayscale pages from becoming muddy blurs.
You could use screen-tone if that suits the story. Look up how to do it correctly so that you don't get weird things happening when you resize your finished page. (The tones can become jarring.)
You could do both…. Does it fit your story to experiment with both or use both, as in @Voodin's example of Jojo's Bizarre Adventure? My first comic was wildly experimental in terms of medium, and I tried everything from pencils, pastels, digital paint, etc. I would suggest to not do that … experiment first. Then pick an approach.
However! I do know people who have gone back to redo their comic. Say they started in black/white and went back with colour. That is a lot of work, but if you find whatever you are doing is not suiting your work, then you are not totally locked-in.
Or, you could use the first two or three pages as colour pages in each chapter, and the rest grayscale.
Or what about colour accents? I read comics that are in greys but for a single colour, for example, red. In that instance the colour red is symbolic, so if you do this there should be a reason.
Ah, all the options! When I teach comics I am really open about medium and approach. There are so many ways to show and tell a story. Make it yours.
(I agree with @Dorian_Grey: colouring doesn't have anything to do with skill. It may mean a skill with colour, but it does not mean a skill in comics or even drawing. I've seen amazing comics in colour, but I have seen ones that could've had much better lines and were hiding the foundation (linework) with amazing digital colour skills, or were coloured and drawn well but had poor flow and confusing action. Whether a comic is black and white or colour has nothing to do with skill or level and isn't really a make-or-break deal.)
Honestly, I have seen such successful comics in everything from colour, black-and-white, to everything in between. Do what you love to do. You will have to love making those pages!
Do what feels right for your story and artwork.