Platinum is not used simply because it is stronger than most metals at high temperature.

It is used because there is a catalytic reaction between hydrogen and platinum that lowers the activation energy of the 2H2+O2 => 2H20 reaction (combustion!).

... the same reason it is used in fuel cells, the catalytic converter in your car, and these nifty Coleman heaters: http://www.sleepingbagsandtents.com/...g.asp?prdc=148