For basic FP, I agree. Really, at this point I think basic FP is necessary in almost every programming language – from JavaScript to C#, that’s been an assumption for a long time – but in Scala it is essential.
But it’s important to keep in mind that there are multiple definitions of “FP” floating around. Closures and higher-order functions are a core part of the language, and it’s very hard to get anything done without them. On the other hand, there is pure FP – writing in a strictly functional style. (What I think of as “Red Book Scala”.) That is not usually mandatory; most Scala programmers don’t work in that style. (I’m finally getting into that style, after 10 years of Scala programming.) Moreover, if you are used to OO style, it tends to be quite a bit more work to learn. So I don’t usually recommend starting out there unless it is a specific goal of yours – as @sidhartha11 has shown, trying to learn Scala that way can be significantly harder.
Note: I don’t believe that FP is intrinsically harder – far as I can tell, it’s much easier to learn if you don’t have years of mutable habits to undo. So for a new programmer, I might recommend starting out that way. But for folks coming from other languages, I would take things step-by-step.
As for George’s point about Akka – look, I’m a hardcore hakker. I have been playing with Akka literally since the day Jonas released the first prototype (long before it was named Akka), and my company is entirely built on it. I teach classes on it. It’s useful, and it’s important. But most Scala programmers will never touch it directly, nor should they – it’s crucial for certain use cases (specifically, where you need to be managing in-memory state at large scales), but not for most of them. So I strongly think it shouldn’t be conflated with learning Scala: it’s a separate learning process, and arguably a much larger one if you want to cover all of Akka.
Not to mention, Akka is significantly in tension with hardcore FP programming – while I believe the two approaches are more compatible than many folks claim (and moreso with Akka Typed), they’re certainly very different approaches to building applications at the moment. I rarely hear of Akka and pure-FP being used together – I’ve had to do a lot of experimentation just to push them together as much as I have, and I’ve only taken a few steps in that direction yet. So tackling all three seriously at once is setting yourself up for contradictions…