>>715606They aren't necessarily all worthless. They can be statements of fact.
For instance, if there's an adaption of some kind of another piece of work, you can see if it is or is not faithful to the source material. If it isn't, you can safely skip that adaptation without consuming it yourself and thus wasting time and money and supporting the people who made the garbage adaptation. The same thing applies to historical works. Is it historically accurate or is it not? If it is not, then you can just skip it. Commentary as word-of-mouth can save you a lot of time and can serve the same purpose as reviews, but without the industry bias that most professional critics have.
I know I saved both time and money on that garbage Napoleon movie Ridley Scott shat out because people warned me beforehand that it wasn't historically accurate.