Not necessarily. You need to weight the benefits with the costs. Sure, stamina potions can be bought at NPCs, but mana potions can be player bought - people sell mana herbs all the time, it's just a matter of making them with 99% monday rates every week.
If I run around with capped meditation on, I end up using maybe 3-4x as many stamina potions, without a noticeable difference in mana potion usage. Is it good to use up an extra 3-5k gold on stamina potions just to save about 1k gold on a mana potion? Maybe to you, but not to me.
I'm sure that stamina potions and sunlight herbs are less expensive to buy from players then mana.