That's the main factor then.

If you're relying on sight to find it, then it's irrelevant whether it makes a sound.

If you're relying on sound, you're impeded by the infrequent occurrence. That's would still be the case if the chirping went on with the lights on.

If the chirping requires near total darkness, because then to search by sound you have to go through the trouble of covering the windows (with something more than the blinds or curtains, if there are any) or else you're restricted too searching by sound only in the night hours, and doing a visual sweep by day or lamplight.

(But then the device only chirps in near total darkness, it may be defeated by a relatively dim night light.)