Yeah cold compiles are slow, but most modern tools keep a hot compiler to re-use and once warm a hot compile of hello world is more like ~200ms. There's a bit of complexity managing these daemons, but that's something that the build tool normaly handles for you transparently
Yes it gets better, and the 'fsc' (Fast Scala Compiler) does improve on the situation somewhat; but I've always found it annoyingly slow. It should be mentioned that I haven't looked very hard at that language in many years for that very reason; so things could have improved somewhat. And from what I understand, the next version of Scala (Dotty) is going address this issue (build speed).
