It's one of the most commonly adopted feature among C successor languages (D, Zig, Odin, C3, Hare, Jai); given how opinionated some of them are on these topics, I think it's safe to say it's generally well regarded in PL communities.

It breaks the idea that statements get executed in the order they appear in the source code, but it ‘only’ moves and sometimes deduplicates (in functions with multiple exit points) statements, it doesn’t hide them.

Of course, that idea already isn’t correct in many languages; function arguments are evaluated before a function is called, operator precedence often breaks it, etc, but this moves entire statements, potentially by many lines.

Yes, defer is absolutely a form of hidden control flow, even if it's less egregious than exceptions.

Always gives me COMEFROM vibes.