I picked up one of these the other day:
I thought it might be a nice way to do some fajitas or something similar, and a way to get grill marks. I tried them out with some steaks using a reverse sear. I put the grill pan on the egg under a raised grid. The grill pan acted as the indirect heat barrier, and it started to heat up. A strip and a porterhouse cooked indirect with plenty of oak smoke at 275ish until they were about 125 IT. Removed the steaks and the raised grid and kicked the egg up to about 600 and threw them back on about for about 90 seconds per side.
Grill marks...mission accomplished! This worked quite well for a reverse sear and the nice part is I didn't have to mess with removing the hot plate setter.