I would like to say only one reason why do we face Qibla( only one direction) during namaz.
One of the very important benefit of Salat amongst all spiritual and physical benefits is Namaz teaches us discipline and unity too. Now you imagine if all Muslims they offer their namaz in whatever direction they wish then how it will look. But when we have one direction then at least all Muslims from all around the world have same feelings and way as each and every Muslim has. Otherwise if it wasn’t there we would have different Namaz in different part of the world but since we have one direction Islam is one either it’s in America or in Asia or in Africa and Europe.