I cannot imagine any reason why somebody would want to use RELEASE for production.

A RELEASE is good for installing FreeBSD on a new computer, or for upgrading from a previous major version of FreeBSD, e.g. from 13 to 14 or from 14 to 15.

After installing a RELEASE, you normally update it to STABLE, before starting to use the computer.

STABLE versions correspond to the long-term-support versions of Linux, i.e. they include only essential back-ported patches, like security patches or bug fixes.

RELEASE are the initial versions, like a Linux x.x.0 version, which may have various problems that are discovered later and corrected in the STABLE versions.

I have been running FreeBSD continuously 24/7 on many servers for more than a quarter of century, and I have always used STABLE on them (after installing RELEASE first, especially when upgrading from an older major version, to minimize the risks of incompatibilities).

Yeah, but which one?

Also, real businesses use -CURRENT, everybody knows that.