What is the purpose of ordinals?

Could you please elaborate on the question, 'What is the purpose of ordinals?'? I'm curious to understand their significance and how they are utilized in various contexts. Are ordinals primarily used for numbering or do they serve other functions as well? In which fields are ordinals most commonly employed, and how do they contribute to clarity and precision in communication? Could you provide some examples to illustrate their usage? I'm eager to gain a deeper understanding of the role and importance of ordinals.