The most visible change I've seen is that I can move funds instantly between my credit union (which I maintain solely for Zelle access at this time in my financial system) and Wise, for free, others would have to chime in for more pireps/ground truth on this which apps are getting this value in front of users.

https://www.frbservices.org/financial-services/fednow-servic... maintains a list of banks and financial service providers currently on FedNow rails.