Using credible sources is important no matter who you are.
As a student, it is important for two main reasons. 1. Say you are making a history report. You need to make sure you get the right information for you report. You don't want to get information that is false, because then you will get a bad grade on the assignment. 2. You also need to be able to demonstrate that you are capable of acquiring proper data. This is a very important skill to have.
As a healthcare professional, using credible sources is crucial. I am not a healthcare professional, but, say for example, you need to research a certain disease that your patient has. If get false info on this disease, you patient may not ever be cured of this disease.
So in the big picture, using credible skills is important because it is a real-life skill that helps no matter what job you need to do.
Hope this helps! :)