No. IMO, shot for shot, it is not more important.
The importance of accuracy has to do with the importance of the shot itself and the rest of the process the photographer uses.
Many LF shooters run very tight ships, that's ok, it's a personal choice.
Other LF shooters use a lens cap, a hat, or a couple dark slides as their shutter, that's ok too, it just means that they may have a little more work in the darkroom than their "tight ship" brothers and sisters.