Author here. Thanks for the question. I'll answer assuming this is a question you have for me.

As explained in the post - the 3090s were what were the test bed that proved the investment was worth it. Customer support, architecture reviews, telemetry to check license compliance. None of that could be done with online models. The amount of time we can spend going backwards and forth with enterprise customers over email can really amplify costs to our team. A few actual issues we found and fixed were listed on the linked blog post: https://www.openfaas.com/blog/painless-support-with-diag/

Having recovered revenue using it in an airgap, to preserve data agreements was more of a cherry on the cake. No need to worry about the investment, it's covered itself.

Hope that helps.