But then I am disagreeing with you lol.I'll start from the beginning since both of us seem to be missing the other's point.
I don't think it matters much at all
I personally don't care about crossplay. Depending on the implementation, I could either like or dislike that a game uses it. On top of that, I don't see the general benefit for people demanding crossplay for certain titles.
Regardless of that, I think it's smart for Microsoft to publicly support crossplay. If implemented it has a positive impact on them since more games are being played in their ecosystem. It's also good PR since they can spin it as a victory against Sony and have fans like them for it, even though both companies have similar amounts of crossplay implemented in games. It's pretty minor and is less beneficial than other things Microsoft does/is working on for Xbox, but it's also relatively cheap to support. It's good bang for their buck even though the overall bang is pretty small.