The topic has been discussed to death and everybody that played all classes knows that medic class suffers… a lot!
SMGs’ niche is up to 9m. After 9m they go from 4 BTK to 5 (same BTK as the ARs). Also, SMGs go from 5BTK to 6 at 25m while ARs only become 6BTK at 50m.
ARs are INCREDIBLY more accurate
ARs also happens to have SIGNIFICANT faster RoF than SMGs beside suomi and thompson
ARs also have bigger mag capacities by default (31 vs 20) than a lot of SMGs (suomi, thompson, MP34 all only have 20 rounds)