I thought this way until I realized I personally value portability over simplicity of signup. Most apps I use often I use on my phone and laptop. When I had an iPhone, I ran most subscriptions through IAP. As soon as I wanted to try Android, moving everything over was nearly impossible.
For most services I now sign up directly through a developer. I also find for services I subscribe to developers provide WAY better customer support than Apple.
For most services I now sign up directly through a developer. I also find for services I subscribe to developers provide WAY better customer support than Apple.