ESPHome switches gain a way to turn on after power returns while keeping their previous state through a restart or wireless firmware update. Makers choose a starting state and storage that survives a software restart but loses its remembered state when power is removed.
This suits a connected load whose supply is also controlled by a wall switch or power strip. A Sonoff S31 test kept its off state through restarts and an update, then turned on after a power cut. Existing restore-mode configurations remain supported.