So in that role (selecting one out of many), it can be used as a one-to-many switch in the construction of the CPU.
Later, I will show you a real one-to-many digital switching device called "demultiplexor". This device can be found in telephone and network equipments that redirect one stream onto one of its many outputs.
At any time, exactly one output signal is equal to 1 (and all other outputs are equal to 0) and the output signal that is 1 depends on the current values of the control signals.
The following figure shows schematically what a 2x4 decoder does. The 2x4 decoder has 2 control signals and 4 outputs: