He really isn't at all.  Reggie Miller is overrated as hell because of his memorable playoff games at MSG.  He's obviously one of the elite GOAT shooters, but that's where it stops.  He had no penetration ability and gave you nothing on defense.
Ginobili can shoot, has a mid range game, can get to the rack at will, has more athleticism, can get steals and disrupt on the defensive end, can pass better than most starting PGs, and is just as tenacious a competitor.
		
		
	 
Ginobli is the better talent for sure, but him being rated over Miller, no you cant do that, Miller carried his teams to the playoffs as the #1 option,Manu was the 6th man, 3rd or 4th option most of the time.
Miller has had season where he was averaging close 25 per game shooting 50% from the field and 40% from 3
Manu's best season was 19 per game on 46% from the field shooting and 40% from 3
If Manu was a starter and played heavy minutes would he be rated over Miller? Probably so, but this is not a game of what if's, all we can go by is what was produced and what is seen.
On second thought you can probably go either way,but I gotta give the nod to Miller,best shooter imo,and stupid clutch,8 seasons of 20+ppg shooting 40%+ from 3 in 6 of those seasons and shooting 50%+ from the field in four of them.