I don't know if this is intentional, but my brain has always connected the word back to the codename used for the nuclear bomb research being done during WWII:

https://en.wikipedia.org/wiki/Gadget_(disambiguation)#Scienc...

The idea being that a code "gadget" is something similarly small and innocuous-looking that turns out to have far, far more powerful effects than anyone would guess just by looking at it.