I was asked recently why a 1/4" seam allowance is not standard for clothing construction, as it is for patchwork.  Aside from the fact that a 5/8" seam allowance has been standard all the years I have been sewing clothing, the wider seam allowance affords a bit of "wiggle" room to adjust fit if needed.  The larger seam allowance also helps prevent stitches from pulling out of seams.  That said, it does make sense for some seam allowances to be narrower when they would be trimmed to 1/4" anyway - like pockets, collars, and other added parts.