+1
These are the ways people can make real money in the stock market:
1) Trade on insider information.
2) Manipulate market sentiment via media releases.
3) Use automation to do high-frequency trading based on complicated algorithms.
4) Buy and hold long term.
1-3 are not available to most Meepers (unless they have a relative in the right position for 1-2, 3 will get you banned), and 4 doesn't make a whole lot of sense for a video game.
Which leaves option 5: penny stocks.
Besides, it's worth introducing because real stocks often come with a benefit that's missing for buyers here: dividends.