The main reason is to shoot 30 caliber bullets from an AR15 while still having 30 round capacity in normal magazines. Suppressors are no more meaningful on this cartridge than on 7.62x39mm or 5.56mm. A lot of people suppress it, and so that leads lots of others to think it somehow needs to be suppressed to make sense.
Here is a 300 yard gel test from a 9 and 16 inch barrel:
Here is a 300 yard gel test from a 9 and 16 inch barrel: