you may be hearing more about scant 1/4" seams because of the increased use of Electric Quilt? i put together blocks for our local shop's block-of-the-month on EQ and lots of people said 'my blocks are measuring 9 1/4" instead of 9 1/2"'. so we talked about the importance of the 1/4" seam, scant, etc. it wouldn't matter so much if you're consistent with all 12 blocks, except that 6 of the blocks are applique with the background cut at 9 1/2". this increases the importance of the scant on the pieced blocks (the thread and pressing do use up some of that fabric), unless you want to trim down your applique blocks. it's a personal choice. we did stress that the 'quilt police' are out on strike for the year due to contract issues, so no worries
anyway, my point is that using EQ's measurements generally requires a scant 1/4" seam (if your cutting is accurate) to get the finished block measurements that you put into the program.
love this hobby!
Patty