Well, then it fits; many terminal emulators don't support \e[5m as blink anymore. Xterm, URxvt, and Konsole do, but the Linux terminal doesn't (gives it a grey background, not blinking), VTE-based terminals (gnome-terminal, lxterminal, ...) don't (ignored), Emacs term-mode doesn't (treats it as bold).
The "gray background" is really a "bright black" background. The old IBM CGA and successors had a flag for whether to interpret the top bit of the background color as intensity or blink[0]. It looks like Linux used to have it set to blink a few years back[1].
