Re: The big problem (and risk) is connectivity
Murder by IoT:
Sneak into someone's house, perhaps via a flaw in their connected lock. Put very heat sensitive compounds close to their dryer and/or oven. Sneak out, wait until they're asleep (and you're safely alibied) and then crank the oven up to full, the dryer on max, and wait for the chemicals to catch fire. I guess after turning the appliances on, for good measure, you could launch a DDoS on their smoke detector, to knock that out of action.