You would get something like this instead of consumer hardware because man hours cost real money. At a previous job they wanted a VR PC, so someone speced out a bunch of high end parts and a case with flashy lights. A couple days of my salary went to putting it all together. That was the first time I had to RMA a motherboard. When I asked they didn't think to confirm the GPU would fit in the case and luckily it did. It also took a couple weeks longer than it should to get up and running because of things like this.

Some specialty software is only certified for specific hardware. You can probably deviate, but it's like building a hackintosh. You might not be able to upgrade it and the man hours will likely kill any benefit.

I also see a lot of managers forget that artists aren't always tech savvy. Honestly, you don't pay them to be tech support, anyway. You want to pay a known quantity and get improved return. It can be a huge time suck to nickel-and-dime when you're tying to manage large projects.

However, using consumer grade hardware has its place.