* separate traits is much clearer IMO:

- the user can see in rustdoc which kinds of memory this library is designed for
- the lib author has one clear model for each, not one complex thing with everything mixed
- if the user has a lib that was designed for NOR flash and wants to use it in an EEPROM they can still do it by using an "eeprom to fake nor flash" adapter that simulates erases by writing FF etc. This makes it work but makes it clear perf will be suboptimal