Yes, it approximates the shape with boxes, but it usually needs a lot less then billions of them…
Compared to the computational complexity of mesh based collision detection the boxes are way faster!
In fact its even so fast that you can dynamicly add the NonConvexMeshCollider component to a shape at runtime and calculate the colliders without noticing any delay.
And apart of the performance advantage, the box colliders have another huge advantage over mesh based colliders:
They can easily be stored as a prefab, together with a game object.
When I paste a code in the “Reedem Voucher Code” it says I have to have an adress registred to my account to reedem a free package. This is a problem whit my account or all licenses are worn?