It doesn't make sense in any world, it only exists to be there so people get to into the checkout flow and throw a few hundred dollars to get it to a usable spec.
The "pro" isn't for work or productivity, its for the appearance of work and productivity. Most people who buy Macs don't really understand what they are getting, developers included.
These "pro" machines have always been known for work and productivity, and 8GB just sounds like a piss poor product decision