Hazrat Moulana Ashraf Ali Thanwi (rahmatullahi ‘alaih) once mentioned:

Apart from the fardh salaah being performed in the musjid, our aslaaf used to perform their sunnat salaah in their homes. Certainly there is great virtue in performing one’s sunnats at home. However on account of the fact that nowadays there are many people who deny the sunnats and have began discarding it completely (i.e. they do not perform it in the musjid nor at home), the ‘Ulama have advised that in order to oppose this group we should perform our sunnats in the musjid (in public) so that we do not resemble those who discard their sunnats. (Malfoozaat Hakeemul Ummat 8/222)

Source: Ihyaauddeen.co.za