Why is UDP lease favored when compared to TCP?

It will depends on the application.

TCP used mostly when communicating with the server. like browsing the net.

UDP used mostly in playing online games, streaming, VOIP, Video conference.

UDP is fast but it is unreliable. It doesn't give any acknowledgment and there will be no retention

Coz UDP is Connection-less protocol and will not give any ack on the data transmission.