Why use response code after making an API request? code example

Example: api response

Response 
				
				 Status code 
				 			2xx -->>  success 
				 			4xx -->>  client side error
				 			5xx -->>  server side error 
				 Header 
				 		meta data about your response 
				 		like Content-Type, Date and some other info

				 Body | Payload		
				 		The response we got from the server 
				 		and this where we do lots of validation