How to effectively use the AA-12?

My Support (25) Build usually consist of the new HZ-12 and DBS. Maybe the healing shotgun if the team needs it. I see no use for the AA-12, as I'm mostly with the team when dealing with Scrakes and Fleshpounds. My method of their disposal is getting right into their face and unleashing the alt fire of the DBS. I can take out a Scrake in around 2-3 blasts, Fleshpounds take a bit more. Besides, it's a lot of money investing in it and no one has room to pick it up if I die. The only time I use it is during Boss fights. Is it worth spending all that money for it?