Servers are generally kept in numerous locations in numerous countries so viruses can't really effect a static server.
Have you read how the nest smoke and co detector works?
"It's based on standard photoelectric tech that sees smoke by shining beams through a "smoke chamber" and detecting how much light gets scattered by airborne particles within. Traditional photoelectric detectors use infrared light with a wavelength above 700nm?and so does the Protect. This works well for detecting large smoke particles of 250nm, but burning items like pine wood or newspaper produce smaller particles of only 50nm.
So the Nest Protect adds an additional blue LED, which shines light at around 400nm. As a Nest whitepaper puts it, "When smoke particles are very small, shorter wavelengths of light, like blue, scatter light many times more efficiently than longer wavelengths like infrared."
Nest calls this system a "Split Spectrum Sensor" and says that the algorithm used to tune it was built from "several hundred data sets, covering a wide range of fire types, including smouldering fires, flaming fires, and nuisance situations."
"Thanks to its built-in humidity sensor, the Protect had an easy time with the steam; it didn't trigger once. (Other photoelectric combos triggered between 30 and 80 percent of the time.) Likewise, the burnt toast tripped ionisation-based detectors 80 percent of the time; the Protect didn't alarm once. (The boiling and frying hamburger tests tripped all detectors a significant percentage of the time, including the Protect.)"
So faster detection and vastly better at false alarms yet because it has one feature where it can be linked to a phone you don't trust it?
Google own nest, how many times have googles servers been taken down by attacks?