Never seen the point myself for road tyres, particularly if you check the pressures regularly (which you should always do no matter what gas is in). The main reason it's used in Motorsport is the ease at which water content can be controlled compared to normal air, and it's like of fire hazard compared against pure oxygen (which you wouldn't want in a tyre).
You are much more likely to get a tiny leak from a valve or rim than you ever would through a tyre.
If it's no cost difference I wouldn't object, but you'll quickly dilute the next time you play with pressures and end up topping up.