That's actually what it is. Professional is the version for end users, people like you and me, who want to run more than "Home" on their own computers.
Enterprise is for computers owned by your company.
Being able to prevent the installation of software is also pretty fundamental. Given that Professional has Group Policy, it's intended to be used within a Windows Domain, and to get a Windows Domain you need a server version of Windows. Which really only businesses purchase.
Yes, professional allows you to attach your own computer to a domain. I guess Microsoft is pretty confident that store apps are sufficiently sandboxed.
Enterprise is for computers owned by your company.