Who coined this phrase, and what is the meaning behind it?
This sales phrase was coined by Elmer Wheeler in the mid-1920s. It urged salespeople to focus on the experience around a product being sold rather than simply on the object itself. It means appealing to the senses and emotions of the buyer with the assumption that this is what motivates most people to purchase. It may be best put by Wheeler himself in this YouTube video.
I don't know who coined it, but I understand the meaning to be: don't base your pitch on the properties of the product; talk about what it can do for the client and how it will make life better for them. In other words, don't talk about how the vacuum cleaner was made in Germany and incorporates the latest technology; tell the client he'll be able to vacuum the house in half the time and he'll never have to buy a replacement bag.