Will a smart plug really turn any coffee maker into a smart coffee maker?

Only if the coffee maker has a mechanical (not digital) power switch that resumes brewing when power is restored. The Proctor Silex 48351PS is explicitly marketed for this use case, and verified-purchase reviewers across Amazon and Home Depot confirm it works with Alexa, Google Home, and Siri-compatible smart plugs. Most programmable machines with digital control panels won't auto-resume after a power cut.