Coming from "make" with repeatable and predictable builds, I was appalled that you run this thing and you have no idea what it will download and what it will produce. Could be something different the next time you run it! Who knows!
I also found it bizarre that even for things that just generate CSS, you are expected to integrate it into your npm thing. I mean, generating CSS from a configuration is a function. It's a make recipe. Why does it need to be an npm library dependency with all the associated mess? I managed to work around it for a number of packages by freezing entire npm setups inside docker containers, which gave me reproducible builds — but it's a losing battle.