Yes in CQB. There have been quite a few shots in tight places I wouldn't otherwise have gotten with even my P90. I run 4 x 50 round mags plus 2 x 15 on backup pistol. Realistically in a 15 minute skirmish, I usually only need to go through 100 rounds, and that's a stretch.
"...However, if preserving the integrity of the gun was the only factor at play then clearly the best option would be to run a 0.0v Lipo and run around shouting 'bang'."