Well, it's more like fruits and vegetables. The author proposed a normalized inner product as replacement for the standard inner product.

It's not an activation function, because it has the learnable weights of a linear projection (mat vec multiplication) and the clamping properties of an activation function all in one.

My personal issue with the proposal is that it essentially doubles the amount of memory needed on-chip.

Yat-Product GEMMV now needs to store the running total of the inner product and the norm of the input vectors. That's a big cost increase for something that might not improve performance all that much.