Demonstratives are used to point to another element that they depend on to achieve their full meaning. If they point backwards, it is known as an anaphoric reference; those that point forward are making a cataphoric reference.
Demonstrative adjectives, which can denote familiarity in an informal style in English, is used with cataphoric references. The demonstrative pronoun, on the other hand, is used in English anaphorically. In Spanish, it is almost always necessary to make the reference explicit.
The use of the demonstrative, be it the adjective or the pronoun, is characteristic of childish and informal language.