I personally learned Scala while at the same time I was applying it to the implementation of machine learning systems, so I think that this is a pretty doable goal.
The book presumes no prior Scala knowledge, although experience with Java or Python or similar would be helpful. I try never to introduce a Scala language concept without formally calling it out and explaining it.
Also, compared to the limit of what's possible in Scala, the FP techniques I use in the book stay solidly in the range of basic to intermediate. There's basically no type level programming, no type classes, no macros (IIRC), and only the bare minimum required use of implicits.
Of course, I absolutely hope that folks will be curious about how to use Scala and FP even more than I show, so this book may be a sort of gateway drug to deeper study in FP, as I talk about in this talk,
Spark as the Gateway Drug to Typed Functional Programming. But that's really all up to you.