I attend the Ordinary form of the Mass. In it the entrance hymn is sung more often than the Gregorian introitus. I've been thinking about the reasons for this.
In the Extraordinary form we find no entrance hymns, I think. But the entrance hymn seems to fit the Ordinary form very well. It really does, although I have even been to Requiem Masses in the Ordinary form in which the Gregorian introitus was sung. It also worked very well.
Personally, I found that Gregorian chant works very well in the OF. Therefore, I don't know why in the Ordinary form people often choose the entrance hymn rather than the introitus in the OF.
What has been the argument for the entrance hymn in the Church? What does the Church officially say about this?