Isnt loop and control two different thing that cant work along?

Answer 1

Not really. With loop an audio or a video keeps repeating itself. This can be usefull as you don't need an audio file of 10 minutes but just one of 10 seconds, for example.
With the controls, the visitor can indeed choose to stop the audio and thus the looping. But maybe he just wants to pause the audio momentarily. Using the controls to pause and eventually play the looping audio again.
If you get what I mean.

Answer 2

well, I tried to remove the controls just to see if the autoplay will start but no, it doesn't. And w/o the controls I can't start the video anymore...