Have you ever used an angle grinder? If not, be prepared for showers of incandescent sparks, lots of noise (bring earplugs), and lots of attention. Not what your typical bike thief is after.

Oh, and what's the price of the extension cord, generator, or battery and inverter to run that grinder? Have you ever noticed how much more expensive and how much wimpier the cordless ones are?

I'm not saying that a bike can't be stolen by a miscreant with an angle grinder, or an acetylene backpack torch, or the Jaws of Life, or any other suitable tool. But it's a little disingenuous to use the fact that locks can be cut with power tools as an excuse to use a cheap lock that can be cut with hand tools.