Yeah... with potions you can carry them around until you need them (or until they go bad).
An equivalent amount of healing - for which you need to go to a clinic in town - is supposed to be cheaper.
On the other hand, Reda actually goes to the people he heals (or that's what it looks like to me), so he really ought to stop undercutting both the Healers guild and whoever makes the potions.
Driving people out of business like that is probably what gets him mobbed in the street by thugs.