This does kind of imply that, if the micro is not busy, then an interrupt is not the right choice; or, to put it another way, that interrupts should be avoided unless performance demands them.

Maybe that's not what you meant, but that's the way it comes across.

Erik calls this "Interruptifobia"

I would tend to agree - interrupts are very useful, and often provide a "better" (sic) solution even when performance is not an issue.
To simply dismiss interrupts unless performance really demands them is unwarranted.