I also got an email notifying me of admission this week to their MA program, instead of their PhD program to which I applied.
Given that I already have an MA from another school, taking this offer seemed very silly, so I turned down the offer, hoping this would allow other potential waitlisted students. Although the program sounds great, it will cost a lot to complete the program if you don't have a scholarship along the offer. If this is the only option which you don't mind paying for your education and also really in need for a MA degree, I'd say go for it. Otherwise, I don't think it would be the best option you'd have as a step for the PhD programs.