I feel like it doesnt matter. They could introduce all kinds of new powerful items such as Holy Grail in the anime and so on which would give more power to the enemy. For example we have no idea what Black Crystal from Nemesis actually was but it gave the clan power to travel in time without Pluto knowing anything (!!!)... It doesnt have to be about Silver Crystal every time.
That's what the 90's anime showed basically as the Imperium Silver Crystal in the 90's anime was the fact a lot less of the big bads were after the thing for them to have.
MANGA
-Queen Beryl and Queen Metaria both want the Silver Crystal to rule.
-Wiseman/Death Phantom wanted both the Silver and Malefic Black Crystal to have the ultimate power in the universe.
-Pharaoh 90 wanted the Crystal as substance/food
-Queen Nehelenia want the Silver Crystal to rule.
-Chaos wanted the Crystal it can one day become Sailor Chaos/Sailor Galaxia didn't want the Crystal just power it up so Usagi and Chaos will kill each other when they fight.
90'S ANIME
-Queen Beryl and Queen Metaria both want the Silver Crystal to rule.
-Wiseman/Death Phantom wanted to destroy the Silver Crystal as it was a threat to his plans.
-Pharaoh 90 needed the Holy Grail to gain entrance into our plane of existence.
-Queen Nehelenia want the Golden Crystal to rule.
-Sailor Galaxia did wanted the Silver Crystal... but only because it was also Sailor Moon Star Seed and even then she just wanted to own it not use it/Chaos showed no interest in it.
I headcanon that the reason why less people were after it in the anime was because in the anime the Imperium Silver Crystal has been known to kill users of it if their not careful enough with it.
This interesting because in the manga Usagi kinda believe that if it wasn't for Silver Crystal people always be fighting over it, starting wars, but as the anime shows that is simply not the case people will fight over things Silver Crystal or not.