Is it fair to build a feature only for some of your (iOS) users?

I am torn. As product person whose job is to understand what's missing and what we could build to improve people's lives, I've always thought that I should try to give the same experience to all my app users, no matter if they're on iOS or Android. However, I've been told that it's dull to not ship a feature of your product (i.e. Ability to play music in the background, while you're not using your phone) just because you can't make it available for both platforms yet. Maybe I am overthinking this? Thoughts?