What is the purpose of the Commerce Clause?
This depends on your point of view. You can look at what it was meant for when it was written -- its immediate goal. Or you can look at it from a modern perspective -- what some people think it can/should be used for today.
When it was written, the point of the commerce clause was to prevent states from erecting trade barriers against one another. The Framers realized the US needed to be one big common market to encourage economic growth so they made sure that states could not regulate interstate commerce.
A more modern reading of the Commerce Clause is that its purpose is to let the government regulate the economy more broadly. Now, this clause is used to justify things like laws regarding the safety of food and drugs as well as things like minimum wage laws.
So, the answer to your question depends on how you are looking at this -- whether you are looking at the original goal of the Commerce Clause or how it has come to be used.