Yes, the Stripe Crypto team started six months ago and the first step was to tune our fiat payment APIs to work with exchanges, on-ramps, and NFT marketplaces. Working on lots more, so stay tuned for more announcements very soon!
The search trend, https://trends.google.com/trends/explore?date=all&q=Fiat%20M..., seems to be relative stable since start of collecting trend data (2004), with slightly increasing volume as we get closer to today, but generally stable.
More information: https://www.investopedia.com/terms/f/fiatmoney.asp
Bitcoin made the term fiat popular.
I don't think this is true, and I also provided a link to Google Trends proving this is not true (at least in terms of "Google Popularity"). Do you have any evidence that Bitcoin made that term popular?