spacepirate
Yeah it would be great for standing or sitting on a bed or the floor any of the situations that are ideal for anything that is 360° like gaming etc.
It's not a big deal to have sounds overlaying each other and if you don't like it you could just mute one of them or even both if you want.
I'm not sure why you seem against this idea are you one of the programers that works on the apps? If I was the creator of the app I could make this idea a reality within just a few hours it's mostly just copy and paste and I would use this feature everyday possibly for years to come and I would enjoy having it and anyone who doesn't want to use it doesn't have to. It would just sit hidden back un-toggled in the settings like it was never there.