Give me a summary of why an abstract is useful in academic literature?

Context: Academic literature uses the abstract to succinctly communicate complex research. An abstract may act as a stand-alone entity instead of a full paper. As such, an abstract is used by many organizations as the basis for selecting research that is proposed for presentation in the form of a poster, platform/oral presentation or workshop presentation at an academic conference. Most bibliographic databases only index abstracts rather than providing the entire text of the paper. Full texts of scientific papers must often be purchased because of copyright and/or publisher fees and therefore the abstract is a significant selling point for the reprint or electronic form of the full text. The abstract can convey the main results and conclusions of a scientific article but the full text article must be consulted for details of the methodology, the full experimental results, and a critical discussion of the interpretations and conclusions. An abstract allows one to sift through copious numbers of papers for ones in which the researcher can have more confidence that they will be relevant to their research. Once papers are chosen based on the abstract, they must be read carefully to be evaluated for relevance. It is generally agreed that one must not base reference citations on the abstract alone, but the content of an entire paper.

Answer: An abstract is useful in academic research because it conveys the complex research in a concise way by acting as a stand-alone summary. Therefore, it is usually used by many organizations as a base for selecting research. Moreover, abstracts are usually provided free of charge by many bibliographic databases which makes the research works more accessible. In addition, researchers can understand if the work is relevant to their research just by reading the abstract.