I am enjoying finding interesting settlements with nice views to use as a base of operations as a change from sticking to orbital ports.
But, how about if you take missions from the settlement and become allied with that faction, you gain level 1 security clearance so you can access some low-level places in the settlement without hacking and such.
Also, with that allied status you get the right to rent a hab as your personal space (if no-one other commander has rented them all before you). You get to spawn in there if you log off there. You also get to transfer and store some ship cargo when you land at the settlement, up to say 100t. Think of it is personal base without the unrealistic base building mechanics of other games.
Also, settlement mission boards should have access to the System News that you see in orbital stations.
Source: https://www.reddit.com/r/EliteDangerous/comments/xg2jfv/odyssey_settlements_how_about/
