Hi
Every business investment opportunity is unique and some offer greater rewards and risks than others. The nature of angel investing is by definition, high risk. Look for deals you feel comfortable with and remember, ROI can be much higher than with traditional investments. Entrepreneurs need these attributes to be successful while you need to recognize it in order to seize an opportunity when you see it.

Do you mean then that "angel investing" is the optimum way for entrepreneurs to invest, or one can become an entrepreneur by being an "angel investor"?

There is one famous saying that "Only the Risk taker will get the more benefit". So, if there is high risk in Business, we can earn more profits.