I agree that for the reasons you explained, MAC address authentication is not very difficult to bypass -- although as schroeder points out, this is difficult on non-rooted phones/tablets. Instead, 802.1x authentication or something like Cisco's MacSec offers far superior security.
MAC address lists are often maintained for other reasons. For example, one can lookup a given MAC address's IP address on the network using ARP. So, from your MAC address list, you can determine what DHCP or static address a machine has, which is useful on occasion.
Other than that, it is useful for keeping inventory and identifying computers on the network when NetBIOS name/etc is not available or has been changed to something you don't recognize.
However, from a security perspective, I would consider MAC filtering to be a deprecated practice with superior, albeit more difficult to implement alternatives available. These alternatives are easier to maintain going forward however than updating MAC lists every time a device is swapped out.
If it is a guest network, fully physically or VLAN separated from any production network, with little need for authentication; then perhaps a token-based system or captive WiFi portal type system would be useful. For example, OpenMesh WiFi devices include such functionality which could allow the receptionist at your office to print out "tokens" for access, which could be unlimited in duration. You could also restrict clients to only be able to connect for x days, so neighbors don't find your WiFi to be their backup internet connection.