The WiFi LED was blue and there were lots of coverage problems at the customer sites . We wrote a blues song "The Blinking Blues" about it and performed it at our offsite. One of the lines was something like "I don't know if it's blinking fast or slow."
Back in the "old days" PCs that failed their BIOS boot had a whole symphony of weird beeps to indicate which failure mode applies. So two short low pitched beeps and one long high pitched beep meant "video bios missing" or something (specific example made up, general idea does apply). I always thought morse code would be an infinitely better user interface. Although I had internet access, this was before widespread adoption of it and well before the invention of the www so you can imagine how much more useful plain english morse code would be for error codes vs seemingly random beep patterns.
I also used to own a pre-ODB2 car which output its "code failures" by a light flashing method very much like the article describes. Three flashes short pause 4 flashes long pause meant engine computer undervolt failure aka its time to replace the five year old battery, or at least it was something very similar.
Besides, you didn't need the internet to look up the error codes when you typically had the dead-tree edition of the same information.
I don't text but my phone had a "ringtone" to announce SMS messages that simply beeped out "sms". I agree that it could have beeped out "GSM 03.41 Short Message Service Cell Broadcast" but "sms" did just as well, much faster.
Strictly speaking, a 1 bit interface is on or off and nothing else. There is no timing in there, no blinking or anything. It's 1 or 0.
If you add time, you suddenly end up with a discrete or even a real function which maps time values to 1 bit. That's however a lot more than 1 bit to encode in total.
If you just think about it, if your device changes state precisely every second for 128 seconds, the entire communication between you and your device is 128 bit even though the lamp itself only outputs 1 bit per time. That's not a 1 bit interface anymore.
One could also add a few blinking states. Slow blink = charge, fast blink = problem, two quick blinks = alert, etc.