I think the lack of syntax highlighting was one reason for that. It makes you think more about the code you write and how it should compose, while a fully fledged IDE encourages you to just throw more code at the problem.
I think the ACME way should be used for love of code and ideally when you want to create libraries that stand the test of time. When you just want to get things done fast bring the full IDE and now some LLM vibes and it’s done.