Not cheaper, as the blend mode is still standard architecture on the GPU
Source*(something) + Destination*(something)
Nothing about this changed/changes. A ‘Multiply’ blend mode preset just doesn’t use alpha, but that will not affect performance; It’s still a blend mode operation as above.
— It’s setup to use the Multiply preset that is standard in Shadergraph… (you’d have to write the .Shader file yourself to make blend modes different from those four default options)
for this to work intuitively for artists it needed the x2 Invert nodes, a computation increase; Though TBF , those two extra nodes are a negligible cost for an easy to use Multiply sprite.