this way of outlining you showed is more or less performant than a shader? what about using SpatialMaterial/NextPass/SpatialMaterial/grow/grow_amount and cull_mode = front
what of them is more/less performant?
If you were to grow the outline's scale, that is to say, animate the vertices moving outwards, a shader would be much faster.
The way it is now, with an outline mesh of a fixed size we fade in and out, the difference is negligible. The cost is maybe one node and one draw call, and you can afford many thousands of them on most devices. So the simplicity / performance gain ratio makes it a no-brainer to me.