What separates the two

The difference is not the name of the company. It is whether you are given work somebody would otherwise have had to do. An internship where a real task falls to you, with a deadline and a person who cares whether it lands, teaches more in eight weeks than a year of shadowing at a famous name.

The tell is what happens if you do not turn up. If the answer is nothing, you are an observer, and observers collect a line on a CV and very little else. Someone whose absence would be noticed gets responsibility, evidence, and a reference from a person who actually watched them work.