

Random programming certificates are generally worthless. The course to get them might teach you a lot and be worth while, but the certificate at the end is worthless. If it is free then it does not matter too much either way, might be a good way to test yourself. But I would not rely on it to get you a job at all. For that you need other ways to prove you can do the job - typically with the ability to talk about stuff and having written some real world like application. Which a course might help you do to.
There is also no way to verify that the software that is being installed is not going to do anything bad. If you trust the software then why not trust the installation scripts by the same authors? What would a third party location bring to improve security?
And generally what you are describing is a software repo, you know the one that comes with your distro.