Well, it practically helps you in making better decisions with your finances, like how much you can invest, how much is the returns, will it be wise to make this kind of investment. Something like that.
I think business cards are important for advertisement. I always take one from people I'm thinking of doing business with to keep in my wallet to call if needed. Even with all the new ways to advertise, business cards are still a good idea.
It helps to advertise the business. But it's not a necessary