That is like asking the question "Does building a solid relationship with the people who buy from you make good business sense?"
If done properly email marketing will increase your profits and viability of your business. It can take your hobby to a full time income.
By building a list of buying customers you increase your ability to reach your customers easily, ask them what they want and then give it to them.
Having a list is your most important business asset.
Hope this helps. What were you planning to do once this question was answered?
