Sorry, I'm coming from C++-ish background - can anyone explain what's going on :)

Scala 2's syntax is mostly Java/C-style with a few peculiarities.

Scala 3's optionally allows indentation based, brace-less syntax. Much closer to the ML family or Python, depending on how you look at it. It does indeed look better, but brings its share of issues.[1] Worse, a lot of people in the community, whether they like it or not, think this was an unnecessary distraction on top of the challenges for the entire ecosystem (libraries, tooling, ...) after Scala 3.0 was released.

- [1] https://alexn.org/blog/2025/10/26/scala-3-no-indent/