Basically, the granting organization doesn't want to pay for the full cost of capital equipment that will - either via time or capacity - not be fully used for that grant.
There are other grant mechanisms for large capital expenditures.
The problem is the thresholds haven't shifted in a long time, so you can easily trigger it with a nice workstation. But then, the budget for a modular NIH R01 was set in 1999, so thats hardly a unique problem.
I can think of a few ways to abuse it while still spinning it as "for research". The obvious one is to buy a $9999 gaming machine with several of whatever the fanciest GPU on the market is at the time, and say you're doing machine learning.
So my guess is it's an overly broad patch for that sort of thing.
There are other regulations to keep people from installing Steam on their ML workstations (which also cover machines below the threshold).
It's entirely about one grant-giving entity not wanting to pay for a piece of capital equipment that will have use beyond the project they're funding. It's a federal regulation, and it comes up far more commonly with lab equipment than it ever does with computers.
There are other grant mechanisms for large capital expenditures.
The problem is the thresholds haven't shifted in a long time, so you can easily trigger it with a nice workstation. But then, the budget for a modular NIH R01 was set in 1999, so thats hardly a unique problem.