The collar sleeve position is a great starting point for setting up your attacks from your open guard. Super effective for setting up the omaplata and triangle as well as some of the newer movements such as the berimbolo, farside collar sleeve, and matrix style attacks.
Common issues that I see with lower belts is that during grip fighting exchange their attention is spread out over two or three different focuses. From this also not knowing when a guard is compromised and no longer defensible. If you underrated these two major details. Your guard game is sure to level up.
Grip fighting from guard is an essential part of playing guard effectively. It’s important that you know exactly what grips that you need and which guards you want to play so that there is no lag time in establishing your guard.