Yes, you can successfully use power or frit instead of a solid sheet of glass. Consider examples of Bob Leatherbarrow's crackle (which eventually is often combined with sheet glass, but not always initially), kiln casting with frit, the late David Alcala's "sand painting", Judith Conway's "Mini Landscapes", etc.
The biggest thing to think about is that if you are taking the piece to a full fuse you will need to make sure you use enough glass so that you do not end up with holes. For powder, you need a fairly thick layer since there is air between each grain and it shrinks considerably when fired. As we know, "glass wants to be a quarter of an inch thick". If you don't have enough volume of glass, the glass will move to conform to this rule -- sometimes that is used to the artist's advantage but is a bummer if that's not what you intended
Check out BE's great Tech Note on volume control: https://www.bullseyeglass.com/images/stories/bullseye/PDF/TechNotes/technotes_05.pdf