Transporting from GitHub:
A lot of networks prefer DHCP addresses that are fixed by MAC over individual hard-coded static IP addresses. This can make central maintenance of IP addresses a lot easier. Another benefit is that it would allow to configure a machine in one network, then move it over to another network and it would “just work”.
The feature request is for pi-hole to be able to work with DHCP provided IP-addresses. Upon boot/dhcp-change any configuration file that now has the fixed IP address would then need to be changed.