most people use whatever init system gets installed by their distro and, for the average user, interaction with the init system is pretty much non-existent (what interaction does exist is usually automated through the package manager)
if you’re planning to go into devops, sysadmin, or backend, then learning the ins-and-outs of the init system for whatever is populating your containers is worthwhile (ex. OpenRC for Alpine Linux) but beyond that, it’s up to you where you want to spend your time