Doesn't this program require an undergrad in CS? Why would it be more apropos for another field?
No it doesn't.
"an undergraduate degree in computer science or related field"[0]
[0] - https://www.omscs.gatech.edu/program-info/admission-criteria
Coming to specifically the question, if you need a BS in Computers, then from personal experience, yes, your changes are much much higher if you already have BS.
If you don't, then they'll look into your SOP and related work to see if you good exposure to Computers.