A call option is the right to buy a stock, at a price, for a period of time.

A long call strategy has limited [defined] risk and unlimited potential gains from moves up in the underlying price. Going long on a call is a simple way to gain upside exposure to movement in an underlying security, however the underlying security (such as a stock) must outperform the premium placed on that call by the options market. 

In other words, a long call must beat the options market in order to profit. The long call is bought with the expectation that it will outperform the price of its premium, which is what the options market is pricing in for the most likely bullish movement. There is also no reason to worry about needing to hold a call until expiration: a call can be closed at any time.