Yep. By casting them systematically you have a benefit always available that's supposed to be a limited-use benefit.
What I don't understand is your contention that these are supposed to be limited use benefits. Where dose it state that?
The game is designed such that it is up to the player to decide whether they are used in a limited fashion, or always available (shy of extremely unusual circumstances), or not at all. Systematic casting of spells is a feature of the game.
Sorry, I don't get it. Why would a DM even want to intrude into the decisions of a player for something that the game pretty much gives the player total control over for his PC? Why would that bother a DM and why would the DM want to p__s in his player's cornflakes over it?
I don't decide how my players roleplay, Why would I care about what spells they cast every day? Yeah, maybe if the spell was unbalancing the campaign in some way (like Animate Objects has the potential to wreck one encounter per spell slot).
Sure, if the DM wants a Gritty Realism feel in his campaign as per page 267 of the DMG, then fine. Mage Armor then DOES become a benefit that's supposed to be a limited-use benefit. Absolutely.
But as the core game is designed, that's not the case. That's a variant rule. The game is designed for Mage Armor to more or less be available whenever the player wants it to be.
If you were in an area with tight enough water rationing you might feel differently. If said rationing weren't tight enough to influence your behavior, it's prettymuch not rationing.
Except that I don't live in a Gritty Realism campaign world. That variant rule has not yet been implemented. When it does, the rules will change. In the meantime, rationing is not needed and Mage Armor can be cast every day.
