the use case is, that an employee takes a Z1/Z3 with him on a biz-trip. in the hotel-room, there may no wired connection and there is neither a cellular data card (or USB-LTE-stick) available. BUT, the hotel provides free WLAN access → if a Z1, Z3 could directly use the hotel-WiFi in station/client mode (in addition to AP-mode), the employee would be pretty happy.
if the cameras WiFi can connect in station (aka client) mode to access the internet - and a GUI of some sort, to configure that mode, is developed/available - that code should be integrated into the Z1 / Z3 series as well. it would provide a 3rd way to get an internet connection: ethernet, USB and (new) WiFi (client-mode).
IMHO that feature should be merged into MX64W and MX65W as well.
and yes, the MR products have a similar function: automatically switch to repeater-mode within a meraki-WLAN or bridge a meraki-VLAN to ethernet using a meraki-WLAN. this works nice within a fully deployed meraki environment (which i like and prefer very much, of course!). but it may happen, that you want to bridge a non-meraki WLAN, or use that WLAN as internet connection. (again) if you have a way to setup WLAN-client-mode on the cams, then there are use cases for this feature also on Z1, Z3, MX64W, MX65W and also on the MR.
hope i could explain good enough.