Comparison to boolean

Enums are very similar in spirit to booleans.

A boolean has one of two values. true or false.

An enum also has one of a fixed set of values. The difference is that each item in this fixed set can have its own name and that there might be more than two values.

Depending on context and personal taste, it might even make sense to use an enum with two variants as a replacement for a boolean.

enum Power {
    ON,
    OFF
}

void main() {
    Power power = Power.ON;

    if (power == Power.ON) {
        System.out.println("The power is on");
    }
    else {
        System.out.println("The power is off");
    }
}

The benefit here being that the names you give to the enum and to the variants might be clearer to read in code than boolean, true, and false.

The downside being that you needed to write more code.