"You don't trade the market, you trade your beliefs on the market". This is a quote from the late Van Tharp, who was one of the most well known trading coaches.
The market is an abstract entity. Investors and traders "meet" at the Stock, Options, Futures Exchanges, and trade their beliefs, buying or selling, every single time the market is open.
By design, the market, in the medium and long term, is structured to go up. For instance, the average yearly return of the S&P 500...

One of the big challenges traders face is how to control emotions when trading. Once you are on a trade you're at the mercy of the market. You have no control of what's going to happen next.
Papertrade gives you an opportunity to apply your strategies and see if they work. If not, you can tweak and refine your strategies until you  find the right one.
Because you have no money in the line, you will not experience any emotion. Once you found the strategy that works, go live and ...