It depends what you use coffee for. Given that the brain adapts very quickly to caffeine, you lose most benefits from the stimulant effect if you drink constant amounts (and there's a point at which you lose all benefit, even if you start drinking ridiculous amounts of it).

So, it's probably not worth it if you drink it regularly, because it doesn't make you much more alert in the steady-state.

This is unrelated to the other issues it may have.