My apologies as to the tardiness to answer you. This is uncharacteristic of our team but we do have posts that slip past us before we realized and this is one of those.
This is more probably dealing with the security policy where you are than it is something that will substantively improve or degrade your performance. If you choose to join the vCenter server to the domain. That will work, remember that your computer will be a member that computer if domain policies can apply to it, it will. Also for SSO, this allows domain users that have the proper permissions to access the server too. You may want to choose which configuration options to consider here: https://docs.vmware.com/en/VMware-vSphere/6.7/com.vmware.psc.doc/GUID-75D4E587-3F9B-4B50-96DA-D6DB6D1781D7.html. **it also has this telling paragraph.
To configure vCenter Single Sign-On, you must have vCenter Single Sign-On administrator privileges.
Having vCenter Single Sign-On administrator privileges is different from having the Administrator role on
vCenter Server or ESXi. In a new installation, only the vCenter Single Sign-On administrator
(email@example.com by default) can authenticate to vCenter Single Sign-On.
*if the post above has answered the question, please mark the topic as solved.
**All "answers" and responses are offered "as is" and my opinion. There is no implied support or guarantee by the ITProTV team.