I've been rendering digital color exposures, captured in JPEG or raw image formats, to monochrom since about 1995, and have both won recognization in exhibits with them and sold a LOT of B&W photos (probably around 5000, from all different kinds of cameras).
Yes, there is a significant improvement going to the monochrome body
IF your goal is the best B&W photographs. The differences are: improved sensitivity; greater dynamic range (and consequent exposure latitude); lower noise at elevated ISO settings; and improved resolving power at the same sensor resolution.
I can get similar dynamic range in color work to the M10 Monochrom by switching to the 50 Mpixel Hasselblad 907x/CFVII 50c.
The downside to working with a monochrome body is that you have to work the camera in much the same way as you work a film camera loaded with B&W film ... That is, you have to understand the spectral sensitivity of the sensor, visualize what kinds of results you want in the transformation from a color scene to a B&W photograph and use the appropriate B&W filtering to achieve your goals. In other words, pre-visualization of your goals and knowing the behavior of your camera and lens intimately is where you will see the benefits, you will likely NOT see a difference in casually snapping photos and just tweaking sliders around to get a monochrome rendering in your favorite image processing app.
You can feel free to disagree ... I don't care, I know what I see with my own eyes in my photos. I have a lot of experience using these cameras as well as others.
If you want to understand how a monochrome camera sees the world differently from a color camera, and how it responds with different filters and different lighting, you
must test your equipment and analyze the results. Here is a pair of charts of some of my basic testing with a controlled light source and an Xrite Color Checker with my M10 Monochrom, and the five B&W filters (Red, Orange, Yellow, Green, and Blue) that I use with it. It should give you a reasonable idea of how the sensor responds.
M10 Monochrom - Graphs
M10 Monochrom - Swatch comparison
Beyond that, you have to do a lot of shooting in different lighting situations with different subject types to fully understand both how to get the most out of a monochrome camera and how to expose properly with it.
If you don't understand these things, and develop the skills and the approach to using it to its limits properly, then using a color camera and developing monochrome images by rendering down that camera's captures will net pretty similar results. And they can be very good results ... but they are simply, clearly not the same.
Good luck!