I guess you got me wront here. I am indeed using the device with a bluetooth dongle. It workd perfectly with the pi itself but when I am using the NESPI Case, I don´t get enought current for pairing a new controller. This is due to the fact that in order to pair a new controller, you have to connect it via USB . And as soon as this is happening, the pi doesn´t get enough current, resulting in strange behaviours. Such as: Restarting itself, working USB-Connection but not working bluetooth dongle or vica versa. However one cannot connect new devices to the dongle. If you take away the case this is working. And I guess if you are willing to buy yourself 4 Controllers which you will only use with the Nespi and never ever with some other device, this may do the trick but then again.... 30 Euros for a device with a lacking current in terms of powering a single bluetooth dongle and one USB-Controller for the sole purpose of connecting it via Bluetooth and not powering it as a whole, is one f**king mess and I also think a rip of. I think I will do a hardware hack and cut wholes into the box, so use the normal pi outputs instead.
I was just asking here because I was curious if I have gotten a faulty device. But if everyone has these issues it is just pricy crap.