e.g. 1 baud, then anyone with a stopwatch or a second hand can just read the bits.
Include start or stop bit? data length as many data bits as needed? bit order? while looking at the stopwatch and looking at the led, you also have to write down the 'bit values' and decode them. I'll bet you
wouldn't do this.
Here's a video of my previous post, displaying temperature-
https://photos.app.goo.gl/SDRRb3Ki9Ddivf2QAsomehow I doubt anyone will have a hard time decoding the temperature value, without any instructions.
flashing an LED to show a 10 bit ADC result
The value will have a higher meaning than a simple adc value, so you would be displaying 'something' but you wouldn't call it an adc value, and most likely not use as-is. It will be a voltage, temperature, position, etc., and that will be the value you want to communicate.
I'm aware that the flashing of a single LED to show diagnostic trouble codes is used on motorcycles. What else is used?
Without wires/wireless and no display of any kind, there is a good reason blinking an led is the solution- its self contained to the code producing device and is a 10 cent part. Beeping the horn, flashing the headlight, cranking the starter, flashing the brake light, etc., are all worse solutions for multiple reasons.
Its not a big jump from single led to single 7 segment led, or multiple led's, but it could be that anything other than a single led is simply more complex than what is needed. It could also be reading from 10' away is easy with a single led, and difficult/not possible to read with multiple led/7seg led(s) at that distance if distance is a factor (that could also apply to lcd or any display).
Wireless is cheap enough now, and is what I do for temperature around the home (broadcast via ble, read on smartphone with no special app needed), but blinking an led to communicate temperature outside 10 feet away is not a bad minimal solution, unless you plan on putting it in direct sunlight. Blink codes via led is also a good solution to communicate problems in an mcu.