A&S could break that stigma down. No one's lying about where it comes from: A&S discloses its relationship to The Boston Beer Co. on its website (albeit deep in Newman's rambling mission statement), and on BBC's site, you can find mention of the subsidiary after a few clicks.
A&S' brands are subsidiaries. But because they're backed by serious craft brewing heritage & know-how, these subsidiary labels have a better shot to gain traction within the notoriously insular craft community. As the market becomes more saturated and brewers continue to consolidate, that sort of open-mindedness to craft-backed subsidiaries is going to be critical.
4. It gives aging brewers another option to sell
Brewer succession is another central question in craft beer these days. Many of the legacy craft breweries -- Sierra Nevada, Bell's, New Belgium -- have leadership closing in on retirement age. There are a few options: establish a stable corporate lineage, sell out (to a macro, or a private investor outside the beer industry), or shut down. A&S could be an in-between option. There's no word on what its expansion plans are, but given the general market trend, it's a safe bet that A) A&S will be looking to scarf up some breweries down the road, and B) breweries' founders will consider selling to another craft company before an outsider.