I had almost the same thoughts reading it. I was like: “wait… putting style class names inside HTML is a bad thing?” WTF? I always did it like this – I am not a frontender and I only occasionally need to write HTML+CSS (mostly for hobby projects) and to me that’s actually a good thing. As you said, less interruptions.
I’d be open to something like LESS / SASS / SCSS as well though. But IMO for most small projects any of those would be a total overkill.