Two uncles of mine conducted their business with the Thompson rather than the Garand even though they “should” have carried the latter (one did so during WWII, the other in Korea). They both specifically wanted nothing to do with two weapons: the M1 Carbine and the M3 Grease Gun.
A former boss drove trucks in ‘nam. He carried a carbine and an M-3. The M-3 was more of a pray and spray deal.