What is the use of bit?

Excuse me, but could you please elaborate on the purpose and utility of "bit" in the context of cryptocurrency and finance? I understand that it's often mentioned in discussions about digital currencies, but I'm not entirely clear on its specific function or significance. Could you provide a concise yet informative explanation of how "bit" is used and what role it plays in the world of digital finance? Thank you in advance for your clarity and insight.