Was just curious as that other person's post got me wondering. LOL
Only reasons I can think of would be to have the ability to use fixed/static IP addresses or just a general IP address that are in the main pool, and I assume would then be picked up by the network map section, where as currently one has to use the wifi log to see the assigned IP addresses for the YazFi guests, and if one wants to use static IP address they have to follow the cumbersome methods discussed earlier in the thread.
The issue, if I remember right, occasionally comes up in conjunction with people using Pi-Hole. If one configures Pi-Hole to poll the router for the device name (used by the IP address) the router doesn't return the YazFi Guest clients because the IP address used by them are not found in the client IP address pool (obviously a problem with the router's firmware by not including IP address ranges used outside the main pool IP address).
So for Pi-Hole users, if they want to have Pi-Hole list the device name they generally had to manually create a Host list on the Pi-Hole device with the YazFi Guest client's IP addresses. This obviously necessitates creating static IP addresses on the router so the Pi-Hole correctly polls the right YazFi guest client every time. I remember one person commenting that this process it (keeping two sets of IP lists, one on the router, one on the Pi-Hole device) was too cumbersome to use as they didn't want to edit both lists every time they added or removed a YazFi Guest client.
I don't add or remove WiFi guests often so maintaining two lists isn't an issue for me at this point.