The barbarian's Acute Vision as an exploration tactic

How does a barbarian who wants to gain low-light vision and darkvision on demand via Acute Vision work? Can they simply declare a "Searching" exploration tactic (as janky as exploration tactics are) that mixes in activations of Rage, or would that be considered a fatiguing exploration tactic?

I would personally say that entering and exiting rage every few rounds is definitely more fatiguing than simply concentrating on a spell, so fatiguing for me.

On the other hand, for the life of me, I can't figure out why concentrating on a spell is more fatiguing than casting a spell each round (detect magic exploration mode)...