Redeeming points in a city where hotels are very expensive like New York City could make the reward points you accumulate worth as much as 35% vs redeeming them for accommadations in Las Vegas where the points may only be worth 12% for the same reward tier.

Basically, a reward category 5 hotel is still a reward category 5 hotel regardless of which city you stay in. A room in New York City may run around $400 while a similar room in Vegas may run only $150.