Any wire, copper or not, is insulated primarily to keep it from shorting against any other metallic object it may inadvertently come into contact with. Shorts cause, at minimum, circuit malfunctions and at worst, fires, electrocutions, and/or loss of life.

Yes, insulating the wire also protects the wire itself from corrosion or other environmental effects, but safety and correct circuit function are, at least in my personal opinion, the primary reasons for a wire to be insulated.

That is basically 12th physics, This coating prevents the wire from charging, helps to control other environmental effects like moisture, humidity, and temperature, and ensures that electricity can safely flow through copper wires.

A copper wire makes it simple for electricity to flow through it, and to protect it from the environment, copper wires are typically coated with insulator materials like plastic or enamel.

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