It shouldn't be to make lots of money! This isn't the stock market. Startups are much riskier and more likely to fail. Greed is a bad reason to invest.
Of course, if you invest wisely, you can make money. Our advice? Invest only in what you understand (and preferably love). If you are a customer and love the product, then it’s more likely it’s a good investment. If you don’t understand it, it may be a bad idea to invest.
Our opinion is that investing should not be solely about earning a return. To invest in something as risky as a startup, you should feel something extra, beyond just the business model. For us, that “something extra” is the fulfillment we feel helping a founder take "their shot" at making our world a slightly better place. We also think it’s pretty cool to learn about different industries when we get updates from the founder.