Entrypoint refers to the identity of a site in a multi-site deployment and when specified indicates that the configuration ...

Entrypoint refers to the identity of a site in a multi-site deployment and when specified indicates that the configuration of the DirectAccess server at that site should be retrieved.
If an entrypoint is not specified in a multi-site deployment then the entrypoint to which the server on which the cmdlet is executed is used. The server could also be represented by using the ComputerName parameter.
If both entrypoint and computername are specified and the ComputerName doesnt belong to the site represented by the entrypoint then the entrypoint takes precedence and the configuration is returned for it.