I see this mentioned a lot in your typical laundry list of "why PvP sucks" type things. People complain that Purify rightfully doesn't do what it says it does - this is because for some insane reason, it isn't set to "first priority" on the spell batching list (and because XIV is a game that for some incredibly stupid reason still uses spell batching in 2022.) We know that it *can* work properly, because DR buffs in the previous system happened instantaneously upon an effect ending.
But then people also insist that Purify/Resilience should function even if it doesn't purge any effects - that you should be able to use it proactively. But this doesn't make sense, because that's why you have Guard. Purify is something you use to break an effect and then gain some immunity afterwards, while Guard is what you use proactively to *prevent* an effect (as well as damage.)
Then they'll also suggest that there *also* be DR timers added into everything else, at which point... CC would be effectively meaningless, which means every game would be a slugging match rather than have any kind of real skill involved. Especially since XIV doesn't have the tickrate to allow for actual, reactive play like WoW does (nor does it have spell interrupts, etc.)