This isn’t uncommon in lots of physics calculations where you are working at the same scales a lot and its cumbersome to keep carrying the constants around and it adds risk of making a mistake.
Think of it as assuming you are working in a system of units where you measure all your speeds relative to the speed of light. So rather than saying the speed limit of a road is 30mph you would say its .000000045c.
This isn’t uncommon in lots of physics calculations where you are working at the same scales a lot and its cumbersome to keep carrying the constants around and it adds risk of making a mistake.
Think of it as assuming you are working in a system of units where you measure all your speeds relative to the speed of light. So rather than saying the speed limit of a road is 30mph you would say its .000000045c.