Because CentOS existed, I made sure most of my open source work would run just as well on all RHEL derivatives as it does on Debian.
If Rocky didn't exist, I would quickly drop all my RHEL support because operating thousands of test machines and containers based on UBI and having to keep up with their licensing game would cost too much of my time.
Rocky and Alma are the only reason devs like me still build anything for RHEL.