Many pianists seem to think that written music and piano improv are opposites of some sort. But I've always found that written music and improv feed each other, so to speak.
You'll learn a written piece and can now see where the composer or arranger was coming from, since you can do this too. And then, when you improvise, you can freely use things you saw in written pieces. There's a flow back and forth between these two things. They're not as alien to each other as many pianists think. In fact, they're coming from the same place, just as spoken and written language do.
It seems to me that Bach knew this, as did Beethoven, Jelly Roll Morton, Bud Powell, as well as Chick Corea, Norah Jones, and Bruce Hornsby. We can too, if we look at it in this way.
Enjoy the journey, and "let the music flow!"