I don't know why anybody would ever get the LicheePi Nano instead of the 4A or the regular LicheePi, because these two boards' main selling point is that they're RISC-V which the Nano isn't.

For some, the physical size is key. Seeed Xiao, Lichee Nano, Beetle, etc fit where e.g. an Arduino Nano won't.

Yes the physical size can be important, and so can the power draw.

Just like you wouldn't use a full-fledged Raspberry Pi for use cases where a Raspberry Pi Nano or other low-power microcontroller is enough.