Comment by grishka

You don't need to understand how the engine works in detail, but in general, it's useful to know which operations are expensive, performance-wise, which are cheap, and what triggers them. For example, you want layout recalculations to only run when they're actually necessary. Or, if you want to move an element around, you should use transform instead of position as transform is "free" because it's a simple matrix multiplication that the GPU does anyway, but position might trigger a re-layout every time you update it.

> I care about building a great CX

I've yet to see a React website that doesn't feel sluggish and overall terrible.

> and making money

Ah that's more like it.