Thats not what makes you a bad diver.....Does that make me a bad diver?
Plastic dive lights need protection, they get brittle from UV, salt, chlorine etc and the first you'll know of hairline cracks is a fizz and darkness in the middle of your dive. If you have lithium batteries, you may be treated to a significantly more impressive fizzle.
Aluminium bodies are way more robust and those you can get way with packing loose in your kit for years and years.