Supporting Linux is a surprise, but I think it's a great move on their part.
Think: How many iOS apps are frontends to a server API? And how many of those APIs are running on Linux servers? Swift on Linux means ~all the code for a client-server iOS app can be written in the same language.
Think: How many iOS apps are frontends to a server API? And how many of those APIs are running on Linux servers? Swift on Linux means ~all the code for a client-server iOS app can be written in the same language.