If a person has the sense and instinct to shoot an attacker several times, this round is a viable choice for the purpose stated by the OP. Probably more deadly than buckshot, on a per pellet basis.
There was a thread about stopping power in TFL a while back. Somebody posted a link to an article by a LEO that had compiled stat's from various gun fights in Chicago. The interesting thing was, all calibers had a similar "fight stopping effect", from 22 lr to 45 ACP.