Doesn't the light diverge instead of converge because we're in the Southern Hemisphere? I think you have to look into the big end.
Other than issues of not being sure of the condition the item is in, and the possiblity of damage during shipping, I don't see any problem. You may get what you're after, you may even get a bargain, but you may also get a dog.
It can be worth it, a few years ago I bought a sonar system off Ebay from a guy in the USA. Sending over $10k to someone I didn't know was a bit nerve wracking, but it turned out perfect, and I got it for 20% of the normal price!
There being no local agent here negated the usual warranty issue that you get with self-imported goods.
Cheers,
Jason.