GMs telling the players that trying something is a waste of time is frowned upon as giving away unsolicited meta-information about the game.
Getting NPCs to do it in-character is clever and cool roleplaying! Also, it had the fun ambiguity of whether they might be lying...
Remember people, puns are a dangerous tool in the hands of the untrained. NPCs should leave puns to trained professionals.
Maybe players should too?
Cassian has a lockpick in his boot?!
I am truly shocked at his sudden usefulness.
And who is this NPC? Not necessarily a rebel, he could just be a guy who got caught up in stuff. Still though, he could be useful for his skills, especially if he knows more about this compound.
Recruiting NPCs is sometimes the key to a successful adventure. They can provide information, perform tasks that require specialised skills, and most importantly, carry things!
And in the end, if things go south with the whole recruitment thing, they can at least be useful for combat training.
Cassian: I get a lockpick out of my boot.
Bodhi: You know it's an electronic lock?
Cassian: It's an electronic lockpick.
Bodhi: It's a waste of time. Not that I care.
Cassian: Who are you?
Bodhi: Why do you care?
Cassian: Are you a Rebel too?
Bodhi: Ha! You Rebels can't even trust each other. Looks like you're in a... splinter cell now.
Chirrut: Oh god, it's one of those NPCs.