> GLSL is fine.

How would you use shared/local memory in GLSL? What if you want to implement Kahan summation, is that possible? How's the out-of-core and multi-GPU support in GLSL?

> People don't understand

Careful pointing that finger, 4 fingers might point back... Shadertoy isn't some obscure thing no one has heard of, some of us are in the demoscene since over 20 years :)