Al these wedding 'traditions' are really very recent. Fashions, maybe, but with no long history to back them up. In the past, ordinary/poor people got married in whatever clothes they had; wealthier people chose a dress thgat they could wear for 'best' for as long as possible after - compared with today, clothes then were enormously expensive. The most famous example of a 'practical' approach to wedding clothes comes from Oliver Goldsmith's 'Vicar of Wakefield' (1766), in which the Vicar writes:
"I was ever of opinion, that the honest man who married and brought up a large family, did more service than he who continued single, and only talked of population. From this motive, I had scarce taken orders a year before I began to think seriously of matrimony, and chose my wife as she did her wedding gown, not for a fine glossy surfaces but such qualities as would wear well. To do her justice, she was a good-natured notable woman; and as for breeding [upbringing/education], there were few country ladies who could shew more. She could read any English book without much spelling, but for pickling, preserving, and cookery, none could excel her. She prided herself also upon being an excellent contriver in house-keeping... we loved each other tenderly, and our fondness encreased as we grew old. "
http://www.ricorso.net/rx/library/authors/classic/Goldsmith_O/prose/Wakefield_01.htm
In Glasgow, at The Tenement House historic building, there is a beautiful late 19th cent wedding dress - in deep maroon silk brocade. I think it might be the one worn by the woman in the centre of this photo.It looks much nicer in real life than in the photo:
https://www.nts.org.uk/visit/places/the-tenement-house/women-of-the-tenement-house
The fashion for white weddings began with Queen Victoria, who married Albert in 1840, and wore white. "This was an unusual choice at the time – most women wore rich colours like red, blue and brown." https://www.londonmuseum.org.uk/collections/london-stories/marriage-queen-victoria-prince-albert/