BBF - there could be two reasons I can see for the 'line up 27 via delta'. The first may be a situational awareness call for other traffic. The other reason may be if there are multiple aircraft at different holding points, then if one misheard the callsign, the holding point would be a giveaway that the line-up was not for the guy at echo or bravo or wherever.
Other than those reasons, wasted airtime I think.
Cheers,
NFR.