Unfortunately this is no longer really the case. PvP gear is PvE gear (for the most part), gone are the good ol’days when PvP gearing actually gave you an advantage in PvP instead of a disadvantage. (PvE gear is arguably more attainable)
I both agree and disagree with your statement, and it all depends on the matter of perspective.
It absolutely on a literal sense lowers the value (gear isn’t as good for as much content), and also increases the amount of work (more gear required = more time).
However there is an argument that also states that “one size fits all” devalues rewards, and because it is easier to access from option A, option B is by default of lesser value.
This can also be extended out to overall itemisation in which obtaining an item devalues all items of that slot exponentially, so once you have a cloak any further cloaks you acquire become redundant. This leaves us with a total of 18 valued items/slots, as opposed to a system with some degree of variance in which you would have 36. (This technically also reduces the chance of "bad RNG on vaults as it opens up more options)
Just food for thought.