I was thinking the same thing. The whole point isn't so much to have a great aerobic system so much as a quickly recovering one. That way, you're ready for the next flurry or takedown or submission attempt ect ect. Some think differently of that like certain boxers but there is a reason you see people like GSP who are at 85 percent when others at at 100. Its pretty awesome.
I do agree that aerobics can be great for recovery. And if you aren't trying to reach a high (elite) level or other things then it is probably more beneficial than not.