They capture different things
Photography captures a moment — held still, framed, permanent. A great wedding photograph lets you look at a moment for as long as you want, noticing details you missed on the day. Videography captures a moment in time — the sound, the movement, the emotion, the thing that happened just before and just after. They're not competing; they're complementary.
The simplest way to think about it: photography shows you what your wedding looked like. Videography shows you what it felt like.