Quick saving is a normal way to save.
Using manual save (aka "save") is good for making up a back-up files in case something goes wrong (like getting stuck in the game from a weird map loading oddity). It's also good if you need to have a save for branching, or going down a point of no-return that you might want to revisit hours and hours down the road.
Keep in mind the game saves automatically when you stay at an inn, and when you change maps. and when you exit the game. So it's not like just using quick save is not saving.