Why does fastlane prevent the use of some ASCII characters in an app's name?

[knewman-chownow]

I am trying to build an app in fastlane that uses an &, but when I run produce, I get the error

Your app name includes non-ASCII characters, which are not supported by the Apple Developer Portal.

Looking at the source code, it seems that fastlane is being significantly more restrictive than just ASCII characters:

fastlane/spaceship/lib/spaceship/portal/portal_client.rb

Line 192 in 63e7559

latinized = latinized.gsub(/[^0-9A-Za-z\d\s]/, '') # remove non-valid characters

I can see that there are plenty of apps on the app store with characters line & or +.

I'm just curious if there is a particular reason for the tight restrictions, if they might be improved in the future, or if I should look into alternate naming conventions for my app.