If your goal is to get the most $/point, that is typically done by transferring to an airline or hotel.
At best you can get 1.5 cents per point (cpp) through the Chase portal, for example. But by transferring to an airline and booking business or 1st class tickets you can sometimes get 10+ cpp.
One of our best redemptions was business class flights to Paris at 20cpp
https://www.gocurrycracker.com/to-europe-and-back-again/If your goal is to get the most economy flights or hotel nights per point, sometimes transferring is best / sometimes using the card portal is best.
For airlines, if you book a fare through the card portal you will still earn miles for the flights (no points for award travel)