Popa
When Davening the Kavanah should be sincerely for the other person, its wrong if the whole intention of Davening for the other is for yourself to be answered. The point is you daven for someone else too and therefore you will also get answered quickly.
But if each one is focusing on themselves it probably won’t be very effective because the whole zchus is that because you are Davening for another you “deserve” to be answered “first” but if you are only doing it to be answered first you cancelled out the zchus. Or so it seems.