In some cases today that hostname is being resolved via mDNS, which is a good reason to get into the habit of using .local for mDNS addresses. Using somehostname.local on many OSes today forces DNS lookups to always and only use mDNS and avoids accidentally calling DNS. (So long as you don't break mDNS support on your local network by doing something like trying to use .local for traditional DNS.)

mDNS is probably sufficient for most people and you don't need to setup old school DNS on a local network. (But if you do, a purpose-built TLD like home.arpa is a good choice.)