IIRC, when there was only the NMOS Z80/Z80A parts, this was one of
the reasons for the popularity of the Intel 8085. You could put
together a functional system for a dedicated application with some of
the made-for-8085 peripherals (e.g. 8155, 8355, 8755), with a very
low chip count compared to what's needed for an equivalent Z80
implementation.
Cheers,
Chuck