Cron jobs are nice and simple to create. Until they go wrong then they are a pain in the ass. You need to manage logging yourself. If you forget you root mail will fill up your disk and crash the system. If you forget the mailto setting. If you remember it you justlose all logs and have no clue why something is not working. You need to redirect the output to a logfile yourself. And then risk filling up the disk with logs unless you remember to also set up logrotate. And you then still don't know when something last ran or if it ran successfully.
So many traps and that is just the logging side of things.

Its hard to argue that 2 config files both multiple lines long is simpler then a single line in an existing file. Adding a service to cron is just simpler. But adding all the extra bit you are going to want on top increases the things you need to learn to do and configure correctly.
IMO systemd timers are simpler to get right at a little bit more of an upfront cost to learning how they work. But cron is still simpler to just get something working without caring that much. I still find that ends up biting you in the longer term though though all the missing features you need to add manually on top of that one basic line you added.