* The institution has a slush / IT fund that provides basic windows laptops or MACs, right off the shelf with lots of security add-ons
* For any non standard equipment or software, the engineers on a project must seek money from the project's budget and justify that cost to the project manager. (not their long-term boss).
* Project managers have a fixed budget based on the proposal they wrote to the funding agency, usually US GOV, with a fixed cost for these kinds of purchases, agreed upon at the time the proposal was funded
* The limited project funds are used to purchase whatever is needed to satisfy the project's objectives. If the project's objectives are not satisfied, the funding agency can stop, or even pull back funding from the project manager
* The approvals for equipment purchases are, at least in theory, given based on merit, which is very often weighed using prior successful proposals. New types of purchases are scrutinized more. If it's traditional to buy CENTOS, then buying ROCKY would be more difficult.
* That precedent is key. Once it becomes clear that ROCKY is being used by successful teams, then the approval process is much easier.
That's why this is a big-ish deal (not huge, but nice to see). Now, people writing proposals and working on projects can point to this as precedent. The best outcome is when funding agencies see "ROCKY is better and more cost effective for the teams we've been funding", then you might get a funder to request that teams use ROCKY as part of the proposal requirements. This is almost nonexistent in federal contracts, but is quite common when dealing with military or commercial contracts.
That, and ROCKY can probably now have a NASA logo on their website under "customers", which adds a bunch of credibility to the project, honestly, whether it's necessarily deserved or not based on 3 desktops.