Written down, the terms point and function are almost synonymous. Your point will be your function, and exactly how you determine to create your point clear to your audience can be your purpose. Article writers have true point and an intention for virtually any paragraph which they create.
Authors write descriptive paragraphs because their function is always to describe something. Their point is one thing is gorgeous or disgusting or strangely interesting. Authors write persuasive and argument paragraphs because their purpose would be to persuade or convince some body. Their point is the fact that their audience should see things a specific means and perhaps do something on that brand brand new means of seeing things. Article composers write paragraphs of contrast as the contrast will make their point clear for their visitors.