Well, it may not be as important to the MLBPA as people perceive it to be, but they're still using it as part of the negotiation And I bet if you polled the membership (of non-pitchers that is) the players probably share the perception that it creates a small # of better-paying jobs for them. Which it does, just not, I think, jobs for "DH type" players per se, and many of them will just go to pre-arbitration players too. There was a time when it did more noticeably keep aging LFs and 1Bs employed though.
It won't have a huge impact on the Phillies either way, especially since they're pretty clearly signing a SS and can't trade Segura. With or without a DH they still need a LH power bat more than another defensive OF or utility IF, especially if the SS isn't Didi. But it's also not un-useful to know that JT will be able to make starts there, both this year and going forward.
MLS just announced 2/22 pre-season and April 3 season openers. Perhaps MLB is going to end up in the same place MLS did, which was, they made noise about waiting until you could have fans at increased capacity, resulting in a shortened schedule and May start, but I think they realized the wait was simply going to be too long. But that might just increase the owners' resolve to cancel games.