Sh. al-ʿUthaymīn رَحِمَهُ اللهُ said:

“This is not from the Sunnah, the Sunnah in the sermon of the marriage is to read the Sermon of Ibn Masʿūd رضي الله عنه, and it is famous and known, and if one left it off there is no harm, but it is better to read it.”

Source: Fatāwá Nūr ʿalá al-Darb (10: 110, no. 5055).