It has nothing to do with not being able to get off his block. It has to do with being more versatile when rushing the passer that, instead of going to a second-move to beat the block, he has more options.
That is, in fact, about being a better pass-rusher. Results when rushing the passer.
If both players rush a passer, neither beat the block with the first move, player a goes to a second move and fails to get by the block while player b pulls up, sets himself up, and knocks the pass down....
Why is that not a positive in player b's favor when rushing the passer?
To say that's not anything about being a better pass-rusher is just blatantly false, norm. Both were rushing the passer, one had more success. Come on, you're better than that.
Being an interior DLman also gives you the ability to do this kind of thing, being a rushing OLB unless the QB throws a screen over your head, the ball isn't really in your neighborhood.