Let me rephrase then. Let's assume the check engine light is on due to a fault in the fuel pump. You can clear the code but you aren't clearing the problem. As soon as the problem occurs again, the light returns. In most cases the faults that trigger 'check engine' lights are in a constant state of fault until the part is repaired or replaced meaning the light will return essentially as soon as you press the accelerator.

Clearing the code is a very standard feature of any OBD reader.

It does not mean you get to pass your next inspection. The computer will know it was reset and tell the inspector's computer when it was done. You have to drive ~50/100 miles after resetting for your inspection to be legit. If the problem is still there, it will pop back up.

That part of the video left me confused, because it's often not that easy. I wonder if this function depends on the model.. Also, loose gas cap often goes away after a certain period of time anyway.