Not sure if it was successful when people call it a hell to maintain and newer simpler alternatives like Parcel is gaining popularity.
That being said, the concept of defining a function in, essentially, a config file seems like a step in the right direction. I don't think I'd trust that functionality outside of builds or infra-as-code, though.
It probably only seems like magic because you didn't build a fundamental understanding of how it works before using it. I use some massive webpack configurations and I understand them all quite thoroughly thanks to well-written, modularized configuration files.
Webpack also handles much, much more than just Javascript. It handles CSS, HTML, images, files, pretty much any kind of asset. Java/Scala doesn't have anything like that. Asset management is completely different due to the nature of how assets are transferred to the client.
And Android? Give me a break. The moment you stray from the strict layout of an Android app you run into a wall and have to learn how Gradle operates. This strict layout is good for some but others hate when an environment forces particular constraints upon them.
Webpack is completely configurable at every stage, works with plugins (which compilers don't do) and again, isn't magic. Not knowing how something works doesn't make it magic. That's not what magic means with respect to code.
Besides... Maybe if you just like getting by, you can program in C/Java/etc without learning about compilers. Web dev is fucked and transpiler knowledge is basically required, but sure you can get by in other domains without it. But if you want to be a good programmer, an expert at what you do, someone who lives and breathes and understands computer science, someone who will excel in his career and not remain a code monkey forever... You have to learn about how your compilers work just like you should know how the silicon in your computer is doing its own "magic".
Webpack now does simple config as well with the 'mode: "production"' and 'mode: "development"' presets.