From experience, parsing input into data structures that fit the problem domain once at the "edge" is a good idea. The code becomes a lot more maintainable without a bunch of validation checks scattered all over the place, picking a data structure for the problem at hand usually leads to cleaner solutions, and errors usually show up much earlier and are easier to debug.

From experience though I've found that wrapping all data in newtypes adds too much ceremony and boilerplate. If the data can reasonably be expressed as a primitive type, then you might as well express that way. I can't think of a time where newtype wrapping would have saved me from accidentally not validating or accidentally inputting the wrong data as a parameter. Especially the email example is quite weak, with ~30 lines of code just being ceremony due to wrapping a string, and most likely it's just going to be fed as is to various crud operations that will cast the data to a string immediately.

Interacting with Haskell/elm libraries that have pervasive use of newtypes everywhere can be painful, especially if they don't give you a way to access the internal data. If a use-case comes up that the library developer didn't account for, then you might have no way of modifying the data and you end up needing to patch the library upstream.