Las Vegas annual rental yield > 9% - I must be missing something?

[Robert Hsiao]

A friend of mine recently bought in Las Vegas. He sent over some zillow pages where condos with $800-$900 current rent are asking around $100K. This is yielding about 9%! Even with $170-$200 HOA this seems too good to be true. If I were a renter, why would I pay $800 to rent a condo which, if I buy and fully finance, the monthly mortgage payment is only $600?

Can pros educate me on what I am missing?

Links available if not against any policy; but examples are easily found.