@remiska I think that goes back to the older days when the brides wore a white kimono over red underwear for the ceremony, white signifying death to their own familiy and red rebirth into their husbands. At the reception, as means of showing off their wealth, they would wear good kimono which came with the dowry. A bride might have changed two or three times during the reception, even! For the majority, the kimonos they wore were not that elaborate, but the good kind of formal wear you can use for other important events afterwards, for the wealthy, they were elaborate and otherwise not very practical.
I think in modern times and with the decline of kimono (and dowry, for that matter) that quickly changed to renting stuff and because western weddings seem so much more romantic in comparison to japanese ones, the white wedding dress (which curiously fits the color, even though the symbolism ist totally different) and other fancy dresses, plus fake churches and ceremonies came up.