Electronic shutter is useful when you need silence, very high shutter speeds, or the least possible vibration. That can make it handy for discreet shooting or some tripod/macro work.

Its downsides are mostly tied to sensor readout speed: fast-moving subjects can show rolling-shutter distortion, and some artificial lighting (especially fluorescent or LED) can cause banding. Electronic shutter also usually can’t be used with flash. On some cameras, using electronic shutter may also reduce RAW bit depth to boost frame rate, which can slightly reduce dynamic range.

Mechanical shutter is generally the safer default. It works with flash, is less prone to distortion with motion, and avoids most banding issues under problematic lights. That’s why many photographers use it for general shooting and action.

A related mode is electronic first curtain with mechanical second curtain. It can reduce vibration, but in some cases may produce unusual out-of-focus blur shapes.

In short: use mechanical shutter for most everyday, action, flash, or tricky-light situations; switch to electronic shutter when you specifically want silence, less vibration, or faster shutter speeds and can tolerate its limitations.