Hi,
Unity might have improved things but, using a pool manager for large amounts of objects is still something to consider, this issue will never go away: it's better to reuse something than create it and destroy, especially at high rate and during the gameloop.
if you don't experience any issue, don't use a pool, but if you profile and see pikes when you instantiate objects, then pooling may help ( tho it could be something you do arou d the instantiation that's causing the issue and not necessarly the instantiatation per say, so you need to really pin down the issue before).
Bye,
Jean