"Clever" or "overly specialized", depending on your viewpoint.
Nearly every language has continued to repeat Tony Hoare's "billion dollar" mistake of allowing null to inhabit any type. I think approaches like Rust's and Swift's are steps to stamp out something that never should of existed in the first place.
Perhaps I was unclear. I could not agree more with this assessment (see link to my blog post in sibling).
I was merely commenting on Swift's choice to do it in a (to quote the OP) "clever" way, rather than a general one like Rust or Scala.
https://www.lucidchart.com/techblog/2015/08/31/the-worst-mis...