<Snipped quote by Plumbum>
Depends primarily on how that works. I may need some examples, since having 2018 tech in 1750 would probably be a bit... Well dangerous. Depending on how this ends up evolving.
It means literally the ability to think really fast and perceive (but not act) within bullet time for short periods. Yes, it can be used to invent gadgets but that's still limited to the tech available in the time.
EDIT: In essence, I would write it as the character stopping time to have a think about it, giving half a paragraph of internal monologue of the analysis and prediction of their situation and then acting upon the sudden wealth of information that they have back in realtime.