Suppressors also reduce muzzle flash, reduce that distinctive dust cloud when firing from the prone, and allow the shooter to hear fire commands (and allows you to hear where the enemy’s firing from)
The only problem is that the direct-impingement gas system on ARs funnel really nasty ammonia-containing gas directly into your eyes and nose while firing. Horrible stuff.
Yep, those are all good reasons. Sounds like the SIG rifle system solves or reduces the back flow problem, at least according to their statement.