They do make a very inexpensive tool in the "arsenal" and they can be very useful indeed. I have four thin, two thick.
I use one of the thick as a center "filler" and support for a drip pan, two thin at each end for no particular reason other than providing a nice simple separator for the baskets. Completely unnecessary but, I can't see wasting them, I tried the "split kettle" technique and there are times when it is very useful but, I find I don't use it enough to leave it set up on the 22.
I may revisit it on the 18, I used it for a few cooks and it was fine. Since I got my "KILLER 304 SS" baskets for my birthday, I have the old ones in the 18 and it's not quite properly set for my needs, yet!
The new grill grate literally just arrived at my door so, I will set the 18 up again with the two brick "split" set up and spanking new grate!
A, slightly, late birthday present to myself, thanks, Chad!