Definitely NOT for everyone.  I advise most people to buy and hold real stuff without leverage or debt using dollar cost averaging.  Whether bars of silver or a tank of LPG in the backyard or a farmette by the creek - real stuff owned outright is good.  Commodity trading requires attention to technical matters, fundamentals, and sangfroid - not for the timid or adrenalin junkies either.  It should also only be done with money one can afford to lose.  However, a good technician can pick entry and exit points where the downside risk is less than the upside.
Agreed. Good point about being able to afford to lose the money. That doesn't apply only to commodities but to any risk bearing investment.

Any money that you are going to need to spend should be in a fairly safe investment class such as bonds or cash equiv.

It's OK to take risks with a portion of your equity, or if you are young and have time to earn it back.