GPIO matrix input 1 to many, output 1 to 1

[kolban]

Am studying the GPIO matrix as described in the ESP32 Technical reference Manual (4.1 - Overview) and am reading about the distinction between inputs and outputs. If I am understanding correctly, the input arriving on a pad from an external source can be mapped to multiple of the internal peripheral input signal destinations while on output a single pad can be mapped to exactly one peripheral output signal source.

I think what is confusing me, and the subject of this question ... is under what circumstances might I want a signal arriving at a pad to be seen by multiple internal peripheral signals?

For example, it would appear "possible" to map a pad to be both the input signal for U0RXD_in and I2CEXT0_SDA_in but would semantically appear to make little sense. This then makes me feel that there are examples of semantic mapping that would make sense. In reality, what might those be?

[WiFive]

One reason someone showed was route the input through an internal pad and back out another pad to blink an LED in sync with a signal. If you have some signal that doesn't strictly work with a hw peripheral you may want to use rmt to measure it and also pcnt or interrupt.