~ deltaTime results in more optimized updates according to frame rate changes so that object actions are executed relative to those changes in frame rate
~ Looping physics updates according to changes in rates also lets you do interesting tricks like scale the delta_time (or set it to 0) to implement time-slowing effects or pause the game logic.
refs:
[Rigid Body Game Physics - Great resource!] https://gafferongames.com/post/physics_in_3d/
https://gamedev.stackexchange.com/questions/70255/what-is-framerate-independent-motion