Flying LL is not an operational requirement - it is (was?) a tactic used to avoid detection / engagement by SAM systems iot get in a position to drop a bomb. JSF uses stealth to achieve the same.
Ofc there are cases where you will need to go LL - SOP/SOF for example but it isn't quite the same.
LL is currently a dying tactic - I suspect it has only lasted as long as it has because a. It's the way we used to do it and b. It's fun. Never know, it might come back if stealth isn't all it is sold to be!