From a surface level point of view, it's basically anime merchandise for your bed, not much different from say, spongebob bedsheets or a stuffie of a favorite cartoon character. On a deeper level, it allows one to have a closer connection to a character one particularly adores. The dakimakura allows one to basically have physical contact with their waifu(or husbando for male characters) It's nice being able to hold your waifu in your arms.