Hi,
Formally, the difference is clear enough. Well, off the record: are those 3.3V pins equally intolerant of any use with 5V in the circuit? I suspect, for instance, that the usual LED + resistor arrangement won't kill the 3.3V pin even if the pull-up is connected th 5V. Is it really so?
The Blue Pill: 5V tolerant vs 3.3V standard pins
Re: The Blue Pill: 5V tolerant vs 3.3V standard pins
Accordingly, tolerant pins have diodes that sink currents, but they still require a high enough resistor to limit the currents going into the pin.
For non-tolerant pins you are taking your chances
http://www.emcu.eu/000/STM32_5VtolerantIO.pdf
For non-tolerant pins you are taking your chances
http://www.emcu.eu/000/STM32_5VtolerantIO.pdf