Glad it worked for you. :)

Glad it was helpful! Sorry I didn't respond earlier - I think I need to adjust my notification settings.

The reason this improves performance is because instantiating objects is actually quite costly. Destroying objects also have to be garbage collected, which has its own additional cost. Pooling systems remove both these problems. The overhead from tracking the pool, and disabling/enabling/moving objects as needed, is far less than the performance hit for instantiating and garbage collecting.

Yes, that's the essence of it. The simplest implementation would be to initially spawn however many objects you want (based on performance constraints, how many objects a player might be able to see at a time, etc), and then when you need more, move the oldest one to a its new position. In a slightly more advanced version, you'd disable objects that leave scope instead of destroying them, and add them to an "available" list. Then when you need another, you remove the first "available" object from the list, move it to its new location, and re-enable it.