Electric grills exist mostly because of rules rather than preference: they are frequently the only type permitted on a balcony or in a shared building. Judged on their own terms they are convenient, clean and limited in exactly one way.
Where open flame and charcoal are prohibited, an electric grill is usually the permitted alternative. If that is your situation the decision is largely made for you, and the useful comparison is between electric models rather than against gas or charcoal.
A full-size electric grill draws heavily and shares a circuit with everything else on that breaker. Running one on a long, thin extension lead is both a fire risk and a reason the grill never reaches temperature. Check the wattage and plan for a suitable outdoor-rated outlet.
Electric elements take longer to reach temperature than a gas burner and recover more slowly when cold food hits the surface. Cooking in smaller batches and giving the grill time between them makes far more difference to results than anything else on this list.
Without combustion there is no smoke flavour, which is the honest limitation of the category. A smoker box with wood chips over the element recovers some of it. If smoke flavour is the reason you want a grill, electric will disappoint regardless of the model.
Check whether the model is rated for outdoor use, since some electric grills are indoor appliances that look like outdoor ones. An outdoor-rated unit and a weatherproof outlet are what make it safe on a balcony.
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For convenience, cleanliness and cooking where flame is prohibited, yes. They preheat more slowly, recover more slowly between batches, and cannot produce smoke flavour, so they are a compromise if you have the option of gas or charcoal and a poor one only if smoke is what you are after.
Partly. A smoker box or foil packet of wood chips placed over the heating element will smoulder and add some smoke character. It is a genuine improvement over nothing, but it does not match the flavour from burning charcoal or wood.
They need an outdoor-rated outlet on a circuit that can carry the load, ideally not shared with other heavy appliances. Long or thin extension leads cause voltage drop, which both prevents the grill reaching temperature and creates a fire risk, so a properly placed outlet matters more than it does for a gas grill.