To think that even a fidget spinner could be seen as an accomplishment of science. You learn something new every day.
It's just a (two years late) namedrop to get kids to think about the age-old engineering principle behind a trendy toy.
The real question you should be asking is why they didn't have bearings in the wheels of their relatively heavy and advanced mobile lab, or the motor of their (20th century era tech) ship, and are only making one now when they have far less resources and tools. Or why they think it would be more effective to try snatching something 1) unfamiliar-looking that 2) they might not see coming 3) out of air with a success window of a couple seconds 4) with something they can barely control to begin with. They should have the drone already on standby and close to the interception point when they're attacked which is a helluva lot to ask. Frankly it would be more realistic to have Kohaku shoot the petrification grenade out of the air with a well-thrown stone. Or, if they were to be smart about it, pry it out of their hands after a distributed chemical attack which they can easily arrange now that they have three physically capable moles, several unmanned vehicles, supplies, and a bunch of crafty people outside to coordinate the process and provide backup. But who needs clever, simple, and efficient solutions when you can namedrop popular toys and make the plot a hostage to solutions looking for a problem, amirite?