Rangnick has taken charge at Old Trafford to succeed Ole Gunnar Solskjaer, but he is only interim manager on a deal through until the end of the season.
Red Devils fans have welcomed Rangnick and the German has been lauded for his work in the game at a number of clubs.
But Giles thinks if Rangnick is so good then Manchester United should have given him the job permanently; Rangnick has already floated the possibility he could stay on as manager.
“If this guy is that good, why not give him the job now for two years?” Giles said on Off The Ball.
“Why do you have to wait? If he is worth his salt then he is worth his salt now.
“The deal that he signed, he has the two-year extension in that and that’s supposed to be in a consulting capacity.
“But what’s that supposed to mean? Is he going to be a director of football?”
Rangnick will lead Manchester United into a Premier League clash at home against Patrick Vieira’s Crystal Palace on Sunday as he looks to get his spell in charge off to a winning start.
