Hi Luke, I added to my position Thursday based on potential.
To directly address your subject line as to "Why Buy Stock"? It's an investment/gamble decision. Fortunes are made and millions lost in the markets.
Volatile penny stocks are the most risk and reward scenarios.
Traditional and established companies over the years are the safest. Long term growth stocks which offer dividends and a pattern of success offer more security to a potential investor versus penny stocks.
If you're considering investing, look at a diverse portfolio.
Depending on age (which I haven't with this investment), is to take "70" subtract your age and that is the equation for the maximum percentage you should invest in speculative stocks. The remaining percentage should be in safer investments for your future retirement.
Just my perspective, not investment advice. Good luck in your endeavors.