If you automated the installation of Oracle software by invoking runInstaller in silent mode, root.sh will overwrite the scripts oraenv, dbhome and coraenv in /usr/local/bin. As a consequence, you’ll end up with an older version of the local bin scripts if you ever need to install an older Oracle home.
I prefer to have a deterministic version of these scripts on the server. Therefore, my automation framework always invokes root.sh with the -bindir dirname option, where dirname is some non-used directory. root.sh will create the directory and set the ownership to root if the directory did not exist previously. In contrast, the ownership will be preserved if you create the directory under another user prior to running root.sh.