Just a note to add in addition to the almond/protein connection. It takes the body longer to break down protein than fats, sugars, or any other substance like that. Because proteins are more difficult to break down, you're left feeling full for a longer period of time.
While most nuts have the most beneficial type of fats for health (as opposed to transfats or saturated fats), almonds are particularly good in this regard, and are lower in calories than some other kinds of nuts, like cashews, peanuts and walnuts. While it's also quite healthy to maintain an overall low fat diet, almonds are a relatively good choice for the limited amounts of fats your body requires for vitamin absorption and blood health.
What a lot of people don't realize, too, is that almonds are very high in calcium (for a non-dairy product); so if someone is lactose intolerant, almonds are an excellent substitute for getting some of the calcium the body needs on a daily basis.
I would add that almonds are a good source of protein and protein helps a person feel more satiated. It is usually a good idea to balance carbs and proteins, so a few almonds with a small apple would be a nicely balanced snack. The sugars in the apple would give the immediate energy, but the protein in the nuts would kick in later to help avoid the sugar spike/ sugar low that comes from eating sugary snacks by themselves.
One reason, of course, would be because you like the taste. Almonds can go well with savory dishes (Almond Chicken) or sweet (with chocolate).
As far as health reasons, the major reason for eating almonds is that the fats in almonds are relatively beneficial. The fat is monounsaturated, and that sort of fat has been shown to actually have positive effects on heart health (if you don't eat too much, of course).
Almonds are a real source of beneficial fatty acids that are known for protecting the cardiovascular system. Moreover, they contain antioxidant vitamins, especially vitamin E.
Almonds contain vegetable proteins, with more than 20g to 100g, almost as many as meat or yogurt, which transforms it into an ally of vegetarians.
Beware of bitter almonds (from the wild plant) whose fruit is bitter and it is toxic if it is eaten in large quantities.