You use cron because it does one thing and that's the thing you want to do, so it's easier to use what exists than to reinvent the wheel. The flaw in systemd i

You use cron because it does one thing and that's the thing you want to do, so it's easier to use what exists than to reinvent the wheel. The flaw in systemd is that it doesn't do one thing, it tries to do everything. Instead of launching tasks with cron, logging errors with syslog, preventing parallel execution with flock etc., systemd tries to do all of that. Worse, it assumes that once you use it for anything you'll use it for everything, so if any piece of it is unsuitable it's not as easy to swap out only the unsuitable bit for an alternative. The result is that the things it was specifically designed for are easy, but they were pretty easy already, meanwhile the things it wasn't specifically designed for become significantly more convoluted than they used to be.