When Apple tends to make something a default (even if they allow exceptions) it usually means it will be required later. Hint: Change.
App Transport Security
App Transport Security (ATS) enforces best practices in the secure connections between an app and its back end. ATS prevents accidental disclosure, provides secure default behavior, and is easy to adopt; it is also on by default in iOS 9 and OS X v10.11. You should adopt ATS as soon as possible, regardless of whether you’re creating a new app or updating an existing one. If you’re developing a new app, you should use HTTPS exclusively. If you have an existing app, you should use HTT
Source: iOS 9.0 – Apple Documentation