Congrats on the purchase. I really like my rack.
I think the isolators are to help minimize rack flexing & add rigidity when under a load.
If you're planning on carrying and serious weight it's been suggested to run corner guards instead of just the included strips. I'm running the AEV corners and the people I've talked to that run RTTs on the Gobi have been happy with them too.
View attachment 116897
EAD posted on JKOwners another new isolator to add even more rigidity.
View attachment 116896. I haven't had any noticeable flex while carrying my yaks but maybe those running RTTs can speak to this.