If the price of bitcoins goes up, there will be a (not in nominal, but in value i.e. in gold) profit.
Admittedly it would have been a lot easier to just buy bitcoins to make that bet.
Edit: there is also another upside: mined bitcoins are truly anonymous which can motivate a premium in high-friction transactions..
It is true if you mine it yourself. Not if you are part of a pool.
As for the profitability, I suggest that you have a look at this site:
http://www.coinish.com/calc/#It, finally, takes into account the increase in the difficulty.
Don't be fooled by that calculator. It doesn't really take into consideration the coming increase. You have to enter the appropriate increase value to get the "right"(likely) difficulty increase.