This is one of my favorite go-to's for hammy and glute work: the good ol' dumbbell stiff-legged Romanian sammich maker. Or whatever. Anyway, I add a band.
Why? Because when you add a band to a movement it looks sleek and sexy and people think you're innovative. Even when the band doesn't do shit, like on Hammer Strength presses where the resistance curve is already ascending.
Listen, the whole purpose of bands or accommodating resistance is to reduce the "dead areas" in the range of motion. This means they are really most applicable to movements that have a descending or bell-shaped resistance curve. Such is the case with the banded Romanian deadlift.
With this exercise, there's a lot of resistance at the bottom all the way to the mid-range portion in the movement. Then at the top it's like an old man without a strong dose of Viagra: not a lot going on there.
Looping a band around the neck is an easy way to make this exercise more effective and to bring the glutes to the party by making sure there's resistance at the top of the movement, where hip extension is finished.
So as you're in the concentric (lifting) portion of the rep and near the top, you're not losing resistance on the glutes to complete the movement. I also got the stank leg during this set, which is always a good time.