What is the purpose of the key in the remote control?
Do you mean key fob? Ease of carry. Been done like that for years on many manufacturers. Some cars with push button start and proximity keys.
It's a backup key for entry into your vehicle should the battery die in the fob. Depending on the ignition system, you may also be able to start your car using that backup key. Although, most smart start/push button key systems only work via the fob.
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