As long as you get 37s, you'll have to do some heavy wheeling to "need" the lockers. Currently I haven't needed mine yet, and I got really used to needing my lockers in my 2017 JKUR on 35s. I also have the LSD in the back of my gladiator. The BLD works ok enough, in my opinion. It's not fantastic but if you search my posts you'll see the kind of wheeling I do. 37s are the most important upgrade the gladiator needs.
Hey OP...I get your frustration - you thought you were getting one thing, paid premium, waited for arrival and then found out it's not what you thought it would be - I'd be pissed too. Jeep didn't do you any favors with their online info but I think, however, I'd more pissed off at my dealer. It's part of their job to help their customer with questions related to the product and the ordering process. They should have been discussing this new vehicle with you in-depth and insuring all of your questions were addressed - especially since you are a first time Jeep buyer.
Based on your stated intended use, you'll likely be fine and have a clear path of upgrade if you need more. Enjoy the new truck and revel in being one of the first to have the mighty diesel and better gas mileage. Good luck!