SiFive is in the business of selling IP cores and back-end implementation services. The gold standard for IP core validation is "silicon proven" i.e. that it's

SiFive is in the business of selling IP cores and back-end implementation services. The gold standard for IP core validation is "silicon proven" i.e. that it's not just a nice theoretical design on paper, but someone has actually turned it into a physical chip and tested the real life performance. Lots of people will try to sell you their designs and services. Picking the wrong ones can waste millions of dollars and months/years of time. The money spent on this a prototype buys SiFive credibility for both aspects of their business (assuming the chip works) - "we were able to do this for ourselves, so you know we'll be able to do it for you". So it's not a waste, it's a marketing expense, and a necessary one.