It's just an entertainment

It's more fun to watch Depp after knowing who he actually is. You'll interpret his actions, responses, expressions, drastically different. Even though it's the same film you watched.

It's like the first time you watch it, you saw nothing but Frank. And the second time you watch it, you saw Alex the whole time, and no Frank. Crazy magic trick. And after that, if you still watch it, it becomes really fun, or even funny, because you start to see how that is possible.

I think people were expecting it to be a lot better in terms of storyline/dialogue/performance considering the huge budget, the esteemed director and the A-list stars involved. But instead of a riveting thriller, viewers were left with a disappointing shell of a remake. Movies are absolutely allowed to be pure entertainment but that doesn't mean it has to be bad (poorly written; lukewarm performances, etc.)