Eating with right hand is rewardable, but there are certain dishes which obviously cannot be eaten directly with the hand but require a utensil. Therefore, to eat that dish with a utensil but hold the utensil with the right hand is rewardable. This is based on Qiyas with drinks. No one drinks water with their hand, the glass which contains the water is the utensil, but you hold the glass with your right hand. Similarly, if there is certain food that is customarily not eaten directly by the hand but with a utensil, such as spoon or fork, then it entails reward to use those utensils as long as it is with the right hand.