No, the custom builds aren't much more work than the vanilla builds, it's getting the build environment set up in the first place that's a pain, since you have

No, the custom builds aren't much more work than the vanilla builds, it's getting the build environment set up in the first place that's a pain, since you have to build against a different SDK for each version of macOS you support; and the custom builds are what he sells to customers, since with a custom build it can be installed and updated independently of the free-as-in-beer version that is used for things like SSHFS and might be updated out from under you in a way that breaks your application. Updating with your application means that you can test each new version and fix any issues or report back to him before shipping it.