system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars/MCU/General Sci-Fi] Why don't more characters have weapons and equipment unusable by their foes?

In most universes, characters exist that happen to possess superior devices and weapons giving them an edge as a hero (or villain). Their opponent disarms them somehow, or stealthily acquires use of the weapon or tech while the hero is distracted. Of course, sometimes like with James Bond (his Casino Royale biometric signature lockable pistol) or Thor (anyone who is worthy) you'll have the powerful object rendered inert when out of the owner's possession. 

But far too often like with Syndrome and his Omnidroid remote (The Incredibles) or Tony Stark and his Iron Man suits (MCU) you'll have the opposing side taking control of that key *thing* that gives the other person power, and using it against them. Even in cliché villain headquarters we see a self destruct button or command (why would you even have one so easily accessible?) used by a hero who has a casual 10 seconds to spare in their escape. 

Surely you'd employ some kind of safeguard like a fingerprint scanner or password at least. Like with lightsabers, combatants routinely get theirs knocked out of their hands. Sometimes they are used to the lightsaberless person's advantage (Han cutting open the Tauntaun or Finn *something something spoilers*), but a lot of the time it's either lost (see Empire Strikes Back, or any of the Prequels) or collected to be used against their allies (see General Grievous). 

Why aren't more heroes and villains protecting their equipment and weaponry with safeguards? Are there any cases (besides those mentioned) of safeguards being implemented to ensure such a scenario doesn't occur? Even with the Lightsabers, you could employ a fingerprint scanner connected to an internal database that recognises who can and cannot use the weapon, remaining in the default dead man switch "off" mode when released from control by an authorised user (with the authorised users being updated at a Jedi or Sith facility terminal depending on the allegiance of the owner). I get that it's more R&D, resources and time required to get the Prometheans from Halo kitted out with Promethean only gear, but surely it's worth it to prevent any random evolved ape from the other side of the Galaxy from salvaging your weaponry when theirs is depleted far from an allied ammo cache. The Dark Lord Sauron couldn't have crafted the One Ring of Power to make the wearer emit a traceable signal to the forces of darkness whilst also paralysing the individual? 

There's always going to be ways around safeguards, but it seems seasoned combatants and "intelligent" super-geniuses lack some common sense in the "let's make sure only I can use this" department.
gpt
Adding those kind of security on a weapon is one more thing that can stop you from using it. What happens when you're ambushed, really need to shoot back, and darn it, fingerprint didn't register, hang on, I'll jus-

Dead.

For weapons you want them to work every single time. Reliability is the name of the game. Any sort of safeguards puts that at risk.

(Also, Tony Start *had* restrictions on his suits, he added Rhodes to the approval list of Mk2 and Pepper for at least Mk42)