I actually disagree with simplicity. cron does weird things with the environment and it can be hard to correctly reproduce that environment when creating a job and debugging. Conversely, systemd timers are very easy to manually trigger and otherwise behave as a normal oneshot service.
We have a free tool called CronitorCLI that includes a cron-like shell. You can run and test your scripts in an environment that matches how they will be run by cron itself.
As somebody who has made cron jobs my career for the last 11 years, who left a good gig as an engineering director to build a bootstrapped business — that means a lot. It keeps me chugging. Thanks so much.