"So under uselessd a service or socket file cannot depend on the presence of certain mounts, for instance (RequiresMountsFor=). Nor can a service run maintenance tasks periodically with supervision on the maintenance task, and with all the privilege-dropping, isolation, and security features easily accomplished with a systemd service. (And even if a cron implementation implemented such features, they'd work gratuitously differently from systemd services.) Nor can the availability of a device trigger the reliable, monitored launch of a service with all those same systemd features."

Well it isn't called usefuld.