Yes. Mostly it’s what you do, not the amount of parameters. But more things change, the more instructions are needed, the heavier the material.
No. It’s just a convenience but usually (depending on what of course) the function just adds a new block of code.
Material instances?
Literally every instance has it’s own set of parameters.
Ha, no you need specific inputs on functions for the instances to work right.
You MAY get better performance. It depends. Works fine as 1 landscape too, since it is very small all things considered.
loading times aren’t really that bad if you use the proper tools because of instancing. Render thread can get bad quick, but it is dependent on your models.
Personally, I find a loss of 10fps whenever using world comp vs same map tile.
I have a topic about this with reproduction steps in answer hub that no one seems to care about. You could go through it and do the same test yourself to make a determination of what you are better off using.
overall, the landscape material is a tier 1 performance killer. So when you bench mark make sure to use the same material, uniform.