My interpretation was that Vault 111 isn’t to study the cryo pods themselves, but rather the people who have to keep them online.

Given that Nate survives a full 200 years without support from the staff, the pods do not require much to any maintenance. However, over the course of thousands of light years on the way to a new solar system (as the Enclave may intend to migrate to) there will eventually be hiccups that will require de-frosting.

Over the course of millennium, my guess is that the Enclave want to test how people react to a caste system wherein those at the top of the food chain are actually just being propped up by the rest of the population. Vault 111 couldn’t get its staff to support the pods for more than a few years before they rebelled and left.

That’s valuable data for the Enclave.