It's hard to come up with a compiler that produces a sound checker for arbitrarily complex union/intersection types. Perhaps there could be a restriction on reflection to "simple enough" types, but that's always going to be a weirdly moving target based on heuristics. There's already cases where Typescript tries to generate ~40MB+ .d.ts files which are just re-stating the types themselves. So it's easy to imagine a validator compiler emitting 100MB+ of code to check more wild and crazy types.

Size, computation and other budgets seem like useful knobs to expose to developers. And anything that's locally decidable (so can be run on multiple cores easily).