Guide
Best smart plugs for energy monitoring
Smart plugs with energy data are useful when you want both measurement and control. They are a strong next step for espresso machines, projectors, standby-heavy electronics, and schedules you want to automate.
Short answer
Use a smart plug when the real goal is not only to know the number, but also to reduce runtime with schedules, auto-off behavior, or standby control. That combination makes them more commercial than simple monitoring alone.