So far I understood Swift to be the next big thing in terms of hot programming languages with a functional flavor.
Those more proficient with Swift, are posted screenshots manifestations of bugs or are we seeing correct output?
Hoping these are bugs that have been fixed in the meantime.. otherwise this reminds me of Javascript type promotion..
Swift is tightly coupled to Apple's platforms (which are of course commercially very viable, and if you develop for them you should be looking at Swift), under a proprietary license and developed under closed governance. It's a legitimate product, but under those circumstances it doesn't really have a shot at being a NBT in programming by itself, beyond contributing its ideas to wider discourse.
It's obvious that no generally relevant library/infrastructure will be written in Swift, for example; if anyone with a great idea choses to implement it in Swift first for whatever reason, it will be a reimplementation in another, more widely useful language that gains widespread popularity.