Every points booking comes down to one number. But the number that matters is not one cent, it is whatever your own card already gives you for nothing. Pick your points and the bar moves.
Whichever bank or card your points sit with.
This tells you what each point is buying. Take the cash price of the ticket, divide by the points it costs, and you get the value of a single point. The trap is assuming any points booking is a good deal. Your card already gives you a guaranteed rate for doing nothing, and a points booking has to beat that. If your points are worth 1.25¢ booking through your card's own travel site, then a 1.2¢ points booking is not fine. It is worse than doing nothing.