OK, this doesn't usually come up in most games but on the course of a long campaign, especially a war-oriented one, it might;
Suppose your players (or you, as a GM) want to model making home-made explosives like molotov bombs to use against vampires, nail bombs to use against faeries and the like. Then your players get creative and try for bigger stuff. Vampires having taken over that old mine? Drive that truck loaded with half a ton of ANFO into it and watch the fireworks. Want some protections around your home base that will work if someone dispels all the magic? Add some actual landmines and heavy steel doors. Want an intruder-detection system that will actually work against veiled wizards? Bury a couple hundred microtransmitters around the premises and track them by the burnout of technology - you'd get at least an early warning.
And that's just for starters - custom technology can get you custom weapons (like Kincaid's spear and paintball gun), improved vehicles, custom communications (like fiber-optics or wireless networks between shielded systems or fully optical surveillance equipment that can't be hexed) and weird inventions or new uses of old inventions along with magic.
So suppose your players want to make that stuff. How do you judge the effort (resources, contacts, craftmanship, scholarship and others) required for reproducing high-end technological effects? After all, there are people that can make custom tech, custom guns, custom vehicles and the like. And every new invention is essentially a custom job; when Teller, Uram and their team built the first fusion bomb, they basically worked from the ground up. Ditto for Tesla, Edison, Graham Bell and all those guys. Would rules for ritual complexity be applicable to creating new technological devices?
Because I totally have that dream of an adapted A4W mini nuclear reactor operating behind an active major circle beaming the 104 MW it produces through microwave energy transmission systems into a half-dozen adapted Nautilus laser systems that also operate behind separate active major circles to defend a serious base against supernatural attacks. Seeing as radiation does not interrupt magic circles, neither the lasers nor the energy transmission nor the wireless (or automated) control is going to break them so they can fire from inside heavily warded defenses. Yeah, I still remember playing Tiberian Sun.
