I think you are highlighting an important point that are missed by other commenters emphasizing the developer. I prefer GPL over MIT license. But this is a possible fallback if Redis decides to change its licensing (like several others did).

I think these kind of products have strategic significance for MS for their Azure offering. They are probably preparing to offer this there (in addition to and as an alternative to Redis). So, it makes sense for Microsoft to release this with an OSS license (otherwise no one will adopt it).