If you eat with a spoon you're less likely to spill food on yourself or on the floor, especially if you're eating something like rice covered in sauces that can drip and stick to your fingers. It's much more sanitary to use a clean piece of silverware to eat instead, and use a napkin to clean your face afterwards. While some foods are okay to eat with your hands such as finger foods, sandwiches, burritos, etc. it is not socially acceptable to eat rice dishes with your bare hands in most western countries. When in our countries, it's important to remember this when eating out in public and use appropriate table manners to be polite to others.