Why not? I feel like I've had really good luck with them so far. Is it because they're bad for the environment? I do feel bad because I throw them away after each grow, so they're essentially "one use".
I was thinking about switching to those "air pruning" pots which are plastic pots with holes in the sides. From what I understand, you get similar benefits as fabric pots, but much easier to reuse, and also more sterile since it's plastic.