EL AL uses a different system than other airlines which, I can say from experience, is far preferable.

Where would you prefer to spend 15 minutes? In a comfortable lounge, or on an aircraft? Do you enjoy passengers 'from the back' gaping at you as they walk past (maybe this gives some people an ego trip, but it embarrasses me intensely).

EL AL wait until the boarding queue for economy has died down and then begin boarding business class. They then wait until that queue has thinned out and board first class.

In my opinion, far better than 'priority boarding'.