Sadako said:

I agree, the ability to create a perfect 'take 6' digitally is really neat, and would be a great tool for films on shoestring budgets who can't afford to waste film, but I can think of at least three reasons/counterexamples to say that more traditional techniques are better...

Of course, in this era of digital, wasting film is quickly becoming a thing of the past. But even if it were still an issue, turning a character shot into an effects shot might end up costing more than simply reshooting.

Looking at the benefit of traditional techniques from a different angle, the idea of creating a shot that takes the best elements from multiple different takes is appealing, but like any other tool it's not suited for all situations. For instance, if actors have to come into physical contact with each other or they interact with an object in the scene, trying to composite multiple takes may be difficult or impossible. Even in cases where the actors keep enough distance, it may turn out that creating a composite shot from the best takes might yield a flawed result due to differences in timing between the multiple takes. What's worse is that by the time the problem is discovered, a reshoot might be much more difficult/expensive to do.