All it does is installing one small file and thus should be removed to avoid unnecessary rebuilds. https://projects.gentoo.org/qa/policy-guide/installed-files.html#pg0301
Thank you for your report. I disagree here because the USE=xinetd also intoruces a dependency on sys-apps/xinetd which is worth the flag IMO. Also, please read PG0301 carefully again: "Ebuilds must not introduce USE flags to control installing files that are small in size, require no additional dependencies ..." ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Will close this, feel free to comment or reopen if you think I am wrong.