Discrete maths is everywhere. For example a sum has a discrete amount of terms, everything that is countable is in fact discrete. So you are constantly working with discrete objects so it would be strange if things learned in discrete maths never occurred. But for example in statistical mechanics you do a lot of discrete things.
And if nothing else learning discrete maths teaches you how to think, like all maths does, and knowing how to think in new ways is never bad ever. Also discrete maths courses are usually pretty easy since the advanced courses are named after the sub categories of discrete.