[Disclaimer: I have an MSIA]
I think the answer to this question depends on a lot of things. There are tons of pros and cons. I don't regret my MSIA for a second and it definitely helped me land my first job. In InfoSec though, the biggest considerations depend on who's doing the hiring. For malware analysis specifically, I don't think an MSIA will get you from A-Z. You definitely won't develop the technical skills needed to do the job through the curriculum alone, but you might fill some information gaps. I think the biggest benefit would be if you landed somewhere where you have some freedom to do research and work with a professor with a strong background in malware analysis/reversal. You'd probably get a lot more time to develop skills an focus on this independently than you would with a full-time position.
If you aren't already, I'd suggest finding and getting involved with a local security meet-up. There are several national organizations that might meet near you like 2600, OWASP, ISSA, and other local groups. Network as much as you can at the meetups and at regional cons (like a local BSides, or DerbyCon, ThotCon, etc). A lot of cons offer student discounts and you can probably couch surf if you're resourceful and broke (like I was in college). Find people working in the field, ask them the same question. Since they'll likely be in your region, they should have a good feel for how a degree like this is valued near you. You'll also develop a good set of people to call/contact when you're ready to find a job and that's just as important as skill or experience.
Sorry for not giving a more definite yes/no answer, but I hope this helps.