Security is about layers. If I have a basic lock, all I want to do is stop an opportunist.

I have a vehicle that is extremely simple to steal (you can unlock everything with a screwdriver), to protect it I use both a pedal lock, a secret second key and a steering wheel lock.

Will it defeat a determined thief or a team of thieves? No way. However it will put off most opportunists and slow down a more experienced thief enough that they may choose another target.