What kind of working environment requires setting up Vagrant on OSX? It's a Unix-based OS, if you're doing any web development you can do it on the host system.
For one thing, you want the development environment to be as similar to production as possible – same OS version, same webserver version, same DB version, same dependencies, no unwanted extras that differ between environments.
For another thing, you don't want to have to solve conflicts between project A and completely unrelated project T if you need to work on them both.
MacPros have two descent AMD FirePro GPUs but much cheaper to rent.