It's a gamble. The only reason to do it would be if you think mining is a profitable business. And keep in mind that in 2.5 years, the block reward drops from 25 BTC to 12. If you just want to buy BTC, I recommend using an exchange.
I don't know how much you know about bitcoins, but they are designed to make mining less and less profitable.
By the time the next block halving comes you will be making almost nothing with any current hashrate anyway. It is an insignificant fact from the now perspective.
It's as much a gamble as throwing your money in a toilet, flushing, and hoping you will get more money from that. Sure, some will still float on the surface, but it won't be what you invested and certainly no new money will appear.