It's purely a marketing strategy. I will get a macbook pro, but I am not a business person, nor do I make money from my computer work, I simply require programs that use 4-8GB of ram.
To be considered a 'pro' and be worthy enough to use a MBP, you should be using one of these. If not, you definitely own the wrong type of notebook and should consider changing it immediately.
I just have to point out that yours isn't a great example. This is a Pro model, while yours is the newbie-amateur-stripped-down-starter-neophyte-pro-wanna-be model!
As you can see, just sticking the "Pro" name on something, including notebooks, is a marketing term and has nothing to do with specifications or application to any particular person's needs. There are professional doctors who only need a computer to check email, so because they're a doctor is their notebook a "pro" model? There are construction workers who may use a notebook for rendering 3D models of buildings, developing multimedia presentations, etc. that require a more capable notebook. Because that user is a construction worker, is their notebook not a "pro" model?
The fact is, what constitutes a "pro" model is very subjective and means different things to different people. There is no universal standard for pro and non-pro models. It's a marketing term - nothing more.