It seems this is how air bubble works with India..based on rules noted in most airline websites.

You can arrive india from anywhere including transit as you have rights to enter country by citizenship or emergency purposes if you are foreigner
But if you are foreigner and arriving for non-emergency you have to directly fly to india if you are originating from one of air bubble countries and no transit allowed

Same way for outbound..
You can leave india or transit india if you are foreigner provided the final destination is the country you are citizen or have valid visa to enter that country, without any restrictions
If you are indian you can leave india if your final destination is the country where you have valid visa to enter without restrictions, without transiting any other country

Most disadvantage is for travellers who have to make 1 stop flights as this rules out transiting countries. Need to go through airlines who directly fly to india from origin of travel.
Not sure when this scheduled flight ban in india is going to end !!