Think it’s just words to fill in the other side of a trade when giving away a player. Nothing ever seems to come from it.

To my understanding. There is no official documentation I'm aware of which is publically accessible.

Future considerations is basically "something of inderterminate value at a later date".
You can't technically "give away" or "sell" a player for $0. There has to be a legal transaction through either trade, waivers, or loan.
Delaying the return value on a trade and wrapping it in a subsequent deal is a way around it.

It allows players to be moved that have little value, without risking conditional picks.
You can also make trades when you can't quite come to an agreement in time but need the trade completed asap (such as at the deadline).
It can also act as an IOU. One team provides a player to help another and the favor can be returned down the road.

Your replies add to my point, there seems to be no firm/clear understanding or interpretation of what is officially in the CBA regarding this matter.

Thanks for responding. Hopefully someone out there can shed some light on this.