Someone raised this question recently in preparation for our upcoming congregational meeting. Why don’t we regularly applaud whoever sings the offertory? We do occasionally but it is rare when it happens.
D. A. Carson has some helpful insight on the question on page 88 of his book noted below.
Applause used to be unknown. Then it came to be deployed after special music. Now it is sometimes heard punctuating sermons. This is, I think, a regressive step. True, some might consider this to be a kind of cultural equivalent to a voiced “Amen!” I take the point, and would not want to introduce new legalism by banning applause outright. But the fundamental difference between “Amen!” and applause must be noted: the “Amen!” is directed to God, even if it serves to encourage the person who is ministering, while applause in our culture signals approval of the performer. God is left out, and the “performer” may the more easily be seduced into pride. This is one of several ways by which the rules of the entertainment world have subtly slipped into corporate worship and are in danger o destroying it from within.
That about sums it up.
A Call to Spiritual Reformation is a worthwhile read.