Apple Photos: Nuisance Behavior by Design
I shoot about ten different types of cameras a year, dozens of lenses of various brands, and about a dozen different Compact Flash and SDXC cards.
Each and every time I insert a card into the card reader, . There is no preference in Photos to disable this nuisance. And since Apple Photos is dreck as far as any professional use (and an unacceptable risk to any professional workflow that must be dependable over time), it’s a nuisance I’d really like to get rid of. So pops uphere is one way to do that.

disable launching app for card/camera
An alleged workaround is to open select the card icon, and using a tiny little control set it to “No Action” upon card insertion. This must be done for *every* camera card.
(why not Photos itself?!),But this setting is destroyed every time the card is formatted in the camera. Since I do that every time I start a new photo job, this is no fix at all, just a make-work waste of time with no benefit.
To Apple Core Rot and the Apple bugs that never get fixed that waste my time each and every day, add the arrogance of presuming everyone wants to import images into Apple Photos, assuming that everyone possesses only one camera or camera card that is never formatted, and the conceptually vacant design thinking of not allowing a simple checkbox setting to disable the behavior.
Update: I finally just followed my own advice and removed Photos.app. Headache removed.

(preference destroyed every time a card is formatted)