I think you get the gist of most of the replies so far.
magnet status is primarily three things:
1. A marketing tool for the hospital.
2. A money-maker for the agency that confers magnet status.
3. A way to distract nurses by giving them some of the trappings of power and influence through phony committees so they don't go seeking real power and influence through unionization.
Some of us have taken to calling it "maggot status".
I'd also add that, on average, the difference between for-profit and non-profit is probably greater - though even there, too many supposedly non-profit hospitals have taken to acting more and for like for-profits. See this item for an example: