Answer: some PL prof used to do a lot of java back in his day
It's interesting that Odersky started with Modula-2 (implementing a Z80 compiler), did a PhD with Wirth, but there discovered that functional programming offered a level of theoretical rigor and mathematical elegance he missed in Wirth's imperative languages. Wirth was generally critical of the complexity and abstraction often associated with functional languages. Rather than rejecting Wirth's pragmatism, he carried it forward by attempting to make functional programming "industry-ready".
One interesting thing about Scala is that Odersky has both a research background but also is clearly cares about the lecturing/education in his university role also. So they're trying to lean ahead of industry to lead the way on what's possible, but there's also pretty good material on the decisions and how they got there.
It has it's own drawbacks, like all languages, but I appreciate the clarity of their decision making and the communication of what's happening.
Have error messages improved? I remember trying it few years back but the error messages made it hard to debug. Is it due to use of JVM? Sorry for my lack of knowledge since I rarely program in JVM based languages.
Scala is a great language. It's a little bit disappointing that Kotlin is the JVM language that's gained so much traction instead.
Scala was the second programming language I learned (the first was Java). I think I'm quite lucky to have picked up a language like Scala so early in my programming journey. It made it very easy for me to learn new programming languages, since it made it easy to support wildly different paradigms (which is also what makes it hard to use in an enterprise environment).