I thought I'd post this here as it doesn't come up when searching on google, maybe its common knowledge but could be useful to some?
Using transform.localScale on instantiated prefabs results in each prefab having its own draw call which can hugely slow things down. However if you scale up the individual vertexes of each prefab they all get drawn in the same call.
This might get expensive if you're constantly changing the scale of a prefab but if like me you're setting the scale once and...
Draw Call Batching - localScale vs scaling vertexes
Using transform.localScale on instantiated prefabs results in each prefab having its own draw call which can hugely slow things down. However if you scale up the individual vertexes of each prefab they all get drawn in the same call.
This might get expensive if you're constantly changing the scale of a prefab but if like me you're setting the scale once and...
Draw Call Batching - localScale vs scaling vertexes