Right. But that still doesn't make it a rational decision, given that Apple is essentially forcing Photos on all their users. Yes, I could just stick with iPhoto. But since iPhoto has pretty much always supported drag-and-drop onto other apps (as have almost ALL of Apple's apps), I couldn't imagine Photos having next-to-no support for it.
Lets hope things change in future versions.
Forced? Why do Mac users feel compelled to only use default apps? You can't expect Apple to make a basic, standard, prosumer and pro versions. Why not hunt around for the app that meets all your needs?