MVT Digital Direct Peugeot Horizontal AC/LC variable racing ignition

Inner rotor MVT DIGITAL DIRECT, with light, Peugeot Ludix AC / LC

what is variable advance and what is achieved by being variable?
When the engine is at low revs, it is ideal that the degree of ignition advance is greater, i.e. that the spark gap is more advanced than when the engine is revving at full throttle, whose spark gap should be closer to PMS (top dead centre) to extract the maximum power from the engine and to have a more usable power curve.

what is variable advance and what is achieved by being variable?
When the engine is at low revs, it is ideal for the degree of ignition advance to be greater, i.e. for the spark gap to be more advanced than when the engine is at full revs, whose spark gap should be closer to the PMS (top dead centre) to extract the maximum power from the engine and to have a more usable power curve.