Mobs from Lightnings don't despawn

For a very long time, there has been a bizarre and interesting feature that is pigs turning into zombie pigmen when struck by lightnings. This is a very rare and unique ocurrence, and today I saw a zombie pigman that spawned from a pig the first time ever without my own intervention (though there were a lot of pigs from a pig spawner around so the chances were much higher than usual).

Zombie pigmen (or zombified piglins, whatever you want to call it) that spawn in this unique way are unique in were they spawn without a golden sword. I think they should be even more unique, by making so zombie pigmen that spawn from this method should never despawn naturally, unlike regular zombie pigmen from nether or from piglins turning into them in Overworld.

This feature could also be extended to other mobs that appear from lightnings such as witches and charged creepers. I see no point in having these mobs despawn as they are already really rare and therefore have little effect on performance, as well as not being common enough to accumulate in the world.