They cost you much less than would other gifts offering equal satisfaction. If the recipient has a relatively tough time doing something, then their disadvantage can be turned into great gift ideas. Applying this principle requires knowing the recipient's interests and tastes. Fortunately, these are exactly the people we want to please, those we know and care about. These gifts, while quite easy for one person, can be rare and precious to others.
Economists recommend taking advantage of knowledge differences.
For many well off people, discretionary time is the most scarce resource. You may apply your special knowledge or skill toward obtaining something they like but lack the time or skill to acquire. But I knew of dealers in railroad china and surprised him with a memorable Christmas gift. Giving someone with similar tastes a book you've already read and enjoyed takes advantage of this technique. Comparative advantages, disadvantages, and knowledge differences are things that successful people use every day, usually unconsciously.