Remember, the M-1 Caribine was Audie Murphy's weapon of choice, so it had to have some worth on the field.
I own one, a Winchester- and it's an enjoyable (and accurate) weapon to shoot (given it's 50+ years old)
-Back to the BAR, though. One of the advantages was that you could slow down the ROF by adjusting the gas port. One man could lay down the accurate fire of 2 or 3 Garands, (at range) and stretch out the contents of that 20 round box. Just what you need when maneuvering a squad. You can leave fewer soldiers behind to establish a base of fire and send the bulk of riflemen forward.
For a weapon designed for WWI, they got their money's worth.