No, wait... you can write on it.
On the datasheet (Philips 0uo046lw3xgikpf1d0zg15wpefpy datasheet pdf) it says:
The 74HC/HCT4051 are 8-channel analog
multiplexers/demultiplexers with three digital select inputs
(S0to S2), an active LOW enable input (E), eight
independent inputs/outputs (Y0to Y7) and a common
input/output (Z).
What I want to do is write on 8 different pins by using the multiplexer, one at a time by writing each time the selector value and then the pin value. Am I that wrong?