If you ride within the law, obeying all stop signs and signals, and treating other road users with courtesy, then in town you will be accelerating, decelerating, stopping, and starting considerably more often than you would if you were out on the open road.
Lower gears are better for starting and accelerating, and easier for braking. Peak speeds in town are likely to be lower, especially if there are no significant downhills.
You may well be comfortable on the higher ratio on a long flat ride, assuming no strong headwind, but the lower of the two ratios will be far more practical and less tiring in town.