It's never been popular by anybody except RedHat, that's how they sell courses end certifications.
Still haven't found a way to start something after networking has finished when it takes a bit to set everything up. (and no, not going to limit vlans, tunnels,...)
It's a technical 'solution' for a marketing problem.
That's what you would do with the init scripts, as that environment waits until the previous one is finished. (ie you know you have working network) Systemd is in a hurry and there 'after' seems to mean 'not before' instead of 'after <specified> is finished', so after networking is started it advances to the next in line.