My only complaint is it's a bit verbose. I'd rather have it as an option inside the .service file. The .timer requires some boilerplate like [Unit].description (it... uh... triggers a service. that's the description), and WantedBy=timers.target.

This can be solved through abstraction and automation.

In NixOS for example, you can declare a service that runs an arbitrary script every day like this:

{
  systemd.services.your-service-here = {
    script = "echo 'Hello, world!'";
    startAt = "daily";
  };
}

This automatically creates a service file with the script in its ExecStart and an accompanying timer which runs daily and is part of the timers.target.