system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is magnesium, an easily flammable metal used in flares, used to make products such as car parts and computer casings?

Wouldn't it be inherently unsafe to make things from a metal that burns with an extremely hot, hard-to-extinguish flame?
gpt
Sort of, it's certainly a tradeoff.  But you can't just strike a match to a large magnesium block and set it aflame, it has to heat up to 900 F, which is very difficult to do for a substantial block of metal that conducts heat very well and is typically connected to other metal pieces that can act as heat sinks.  

So magnesium is actually quite safe, and it's really only a problem once a fire has already begun to rage (typically the fuel tank is ruptured as well).  For vehicles this is a reasonable tradeoff because most of the time occupants can exit, but you definitely wouldn't want to have a magnesium structure in a building.