What is the ruling on saying "Labbayka, O so-and-so," or "Labbayka, O Al-Aqsa," and similar expressions?

The meaning of "Labbayk" is "I am steadfast in obedience to You," or "response after response." The meaning of "Sa'dayk" is "continuous happiness and delight for You, following happiness." Answering with "Na'am" (yes) or its equivalent is sufficient, but answering with "Labbayk" and "Sa'dayk" is better.