I used to.. but honestly, it gets so out of hand if you slack on pruning the algae. I had caulerpa and chaeto both in my display tank and the caulerpa grows at a pretty unbelievable rate IME and they attach themselves to anything including the sand bed. The chaetomorpha also will get out of hand if you have it in there without pruning, or very little pruning. The chaeto also seems to break apart really easily so it will eventually be EVERYWHERE in your display tank. I had pieces of chaeto on my rockwork, sandbed, powerheads, coral, and pretty much everything. If you like that sortof greenish look then i say go for it.. but i found it to be pretty ugly.
If however you do choose to put it in the display, you can just rubberband a nice wad of it to a rock and then just place it wherever you feel necessary. Just make sure light is getting to it otherwise it won't grow, obviously.
