One of the main objectives of new crew domiciles was a recruitment tool for new pilots. The hiring team knows that the contracts at the big three are similar enough that people will go to the airline that has a domicile where they live. I think that had as much weight as operational reliability, and overnighting cost.
Given that this experiment seems to be on the back-burner at this point, I think that Las Vegas showed that it did not quite pan out the way they had hoped and with the new contract’s forced upgrades, filling CA seats was possibly an even higher objective