I did the NYU Bioethics MA myself, so I'm gonna make a few comments based on that experience, and knowledge from second-hand sources. Full disclosure: one of the Bioethics department staff recommended that I post here, but they're not paying me. Nor is it the case that I felt like I had to help them market in any way.
Basically, an MA can be really useful in prepping you for PhD applications, the PhD in general, and a philosophy career if you can afford it and depending on the program.
I have heard, as fromthearmchair mentioned, that some MA programs don't treat you well. But my experience differs. The faculty at the NYU Bioethics department was incredibly attentive and helpful when it came to PhD applications. The program itself, the discussions, and the opportunities to interact with a lot of fine academics was also awesome. So I've got no complaints (and many commendations) about how the program itself is run. One possible difference maker here is that the Bioethics program is a "terminal" program, in the sense that the department doesn't also offer a PhD that the MA is supposed to lead to. So the faculty actually does give you their full attention. I've heard similar things about other terminal programs vs non-terminal ones.
That said, just having the MA will not increase your chances of getting into a PhD program, or even a PhD program from that university. It may be useful in terms of getting strong references and a better writing sample though. The networking opportunities and the ability to develop more ideas count in the long term too.
In short, some MA programs are great. But it's honestly a tough call whether it's worth the amount that you pay for it, just because it's such a hefty amount (a year in NYU will set you back about US$60K). I am in a PhD program now (first year), and I'm still working on ideas that I wrote about during the MA, so only time will tell if it really pays off for me.
All the best in your applications.