Managers can simply ignore this policy for their reports. If, at the Director level, most of the managers are still of original Slack ilk, this is very feasible. SFDC has unlimited PTO so this won't even be noticed.
Before COVID this was the case with WFH at my last company. I was able to WFH for 2 days a week but it was impossible to get that codified in the handbook. I was even on the committee that oversaw edits/rewrites of the handbook but HR would not let us add anything about WFH other than "It's up to the manager". I had so many people tell me "I don't know why you are so bothered, you are able to WFH". Yes, today, right now, with this manager, or at least this managers current demeanor I have WFH but all that can turn on a dime, I wanted it to be official. "Of course", the company as a whole couldn't allow WFH, that would be "impossible". I left that company in late 2019 and... surprise! They went fully remote in 2020 and now are a hybrid with the majority of people WFH-ing. It was a rare case of being told it was impossible and would never work to seeing not but a few months later all their arguments to be shown for the BS they really were.