Endurance would have to be the reason, yes. I like to be highly mobile in combat (kiting, escaping, setting up
cones, etc.) and will always have Fly or Super Speed or their origin equivalents on. But then you still want Hover and Evasive Maneuvers on for all the in-combat benefits.
I generally don’t build builds that are going to require toggles to be toggled off and on to function. Too much maintenance work I don’t care to be bothered by. There are a few exceptions like debuff toggles where that will obviously happen by default, but, otherwise, I just run ‘em all and build in the appropriate endurance fixes, whether it be procs/endurance discount/recovery in the low levels or cardiac/vigor/ageless/support in the higher levels.