Peat moss is an interesting material, with some unusual properties. At minimum, it has a nice woodsy organic look that makes a good complement to other ground covers. But, if you experiment with it a bit, you will find some interesting behaviors. For example, I like to put some in a jar with a dilute mixture of green hobby acrylic and water. Shake it up, strain, and spread it out to dry. You will find that it clumps up into little globules with a nice look and texture. It is sort of like ground foam, but different, and can be used to break up the "Woodland Scenics" monotony, that can happen when you use too much of one material (not picking on WS, it is just an example of a high-quality commercial source). Peat moss is inherently dark, so you will tend to get dark shades of green, but it is a nice look, and good to simulate overgrown areas of bushes. Here's an example--the area to the immediate right of the horse corral is peat moss:
I think that one of the most common errors made by beginners is to use the same palette of materials everywhere on a layout. This shouts "model" and just never looks natural. That is why I so often advocate for found materials like coffee grounds, peat moss and so on. It is not so much that they are better than the commercially-available alternatives, it is just that they are DIFFERENT. And, IMO the best layouts have more visual variety and texture than you can easily obtain if you limit yourself only to what you can purchase.
