kill-buffer calls frame's buffer-predicate for all buffers even if the killed buffer was not shown in any window.

[Constantin Kulikov]

For example:

emacs -Q

M-: (set-frame-parameter nil 'buffer-predicate #'(lambda (b) (message "f-b-p: %s" b))) RET

M-: (with-temp-buffer nil) RET

C-x b *Messages* RET

See that all buffers listed except of the *temp*(no window buffers were changed). Why?

This is inefficient, especially for the with-temp-buffer which is used very frequently in emacs and in side packages.