No driver, processing or configuration is required on the bridged machine. This is good for devices you can't install a driver on (smart TVs, networked printers, any other appliance). No configuration also means you don't have to risk your wifi password being stored/shared with third parties.
~~Lots of~~ Some* wireless access points support operating in either a client or bridged mode. Client mode usually implies (not always) it NAT'ing the WiFi connection similar to what a home router might do with your internet connection. Sometimes client mode is synonymous to bridging which is what this Pi is doing.
So yes, there's been a market for this on lots of consumer devices for quite some time. Most people just don't know it exists.
Edited my comment a bit as doing a bit more research its not quite as common as I believed but does exist on a number of consumer devices. I still stand by my point that most people don't know about this feature of their hardware when present as most people don't understand the difference between a router and an access point.
Wireless bridges can be useful when you're trying to connect several devices through a single wireless link. Think about potentially having a whole room of devices all with a perfectly placed antenna instead of half a dozen antennas placed in compromised locations.
Similar case, I did this with a home security system when I moved in. It's old but has a web interface for viewing some alarm data, and can technically reach out to the web for sending alarms. The panel is in a closet so the Pi worked perfectly.
I use an intel nuc i3-7100U as a wifi to ethernet bridge for a Windows 10 machine (HP Elitedesk 8300 Core i5-3470). The nuc also serves as a htpc running libreelec.
Why? I tried 4 different USB WiFi dongles with different chipsets spanning ~11 years and each one would end up being the cause of intermittent blue screen of death. The dump file backtrace repeatedly pointed to the usb-wifi stack.