For all the hysteria over facial-recognition technology, the breathtakingly fast arrest of Larry Griffin II for prompting a major subway panic shows that the tech is a boon to law enforcement.

Griffin, a 26-year-old drifter from West Virginia, entered the Fulton Street subway station early on Aug. 16 with a shopping cart and, police allege, two rice cookers that many onlookers thought were bombs — disrupting service for hours.

As reports of suspicious objects started arriving at 7:15 a.m., the NYPD dispatched the bomb squad. Meanwhile, the department’s Facial Identification Section scanned surveillance footage and quickly spotted a clear suspect. Entering color-corrected photos in a program that rifled through hundreds of mug shots, the unit quickly got a good match and circulated a photo to the ranks via cellphone — leading to a collar at 1 a.m. that night.

Facial-recognition chief Sgt. Edwin Coello notes: “Five years ago, you probably have endless detectives looking through [images] . . . It could take several hours or several days. This is the most important type of case that we’d see out there: a possible terrorist.”

The tech’s not failproof, but neither was the human-eyeballs-and-memory system. Most important: Law enforcement must still check all the same due-process boxes. As Police Commissioner James O’Neill put it, “We’re not locking up anyone based on a facial-recognition hit.”

Saving the NYPD hundreds of man-hours so cops can get potentially dangerous people off the streets much faster: That’s not Big Brother, but a win for the little guys.