It allows to easily set a reference value which you are sure it will always be exactly the same.
For me, the value to set when double-clicking on UI knobs would be 12 o'clock (0.5) because turning knobs with a mouse or a touchpad is not easy at all. 0.5 sets the knob at the same distance between the minimum and maximum values.
Personnally, I really like this functionnality on VSTs which have it
It allows to easily set a reference value which you are sure it will always be exactly the same. For me, the value to set when double-clicking on UI knobs would be 12 o'clock (0.5) because turning knobs with a mouse or a touchpad is not easy at all. 0.5 sets the knob at the same distance between the minimum and maximum values.
Personnally, I really like this functionnality on VSTs which have it