They are not exactly the same, but frequently used together.
https://www.thoughtco.com/difference...ecision-609328
Anyway, there have been many posts about the 1/4 inch seam.
In my opinion, which I value highly for my own projects
, how something turns out starts long before the sewing together of pieces.
Fabric preparation - start out with decent/suitable fabric -
In my case, I soak, wash, dry, and iron it before cutting it. I am not a fan of starching/sizing - but will use it occasionally.
Cutting - are my rulers accurate? Most are, but occasionally one is "off". Do you always use the same placement of your ruler when you cut? Are the edges still straight? I've worn down a few so that the edge was curved instead of still straight. It wasn't a deep bow, but still - it was bowed. From the way I cut, my pieces are usually a thread or two larger than the "stated measurement" - example: my 2.5 inch strips might be 2.54 so I do not need to use a "scant" 1/4 inch seam. Measure the cut pieces to check to see what you are actually working with.
I am thinking that if one uses the slotted rulers or die-cut pieces, the measurements might be a bit scanter.
After that, it is worth the effort to do the three strip test to make sure that you will end up with the expected result.
Keeping the seam allowance the same width (consistent) for the whole length of the seam is a good thing. Keeping the seam allowance the same width (consistent) for the whole project is also a good thing.
Especially if it is the "right" seam width.
For something with all the pieces the same size and shape, it usually does not matter if the seam width is 3/16, 1/4, 5/16 - as long as the seam allowance is consistent.
But as the pieces get smaller and the shapes vary, the seam allowance does matter - if one wants to get the desired results.
Absolutely no new information in this post - I sometimes need to remind myself of it, though!
PS - as far as that 1/4 inch seam - I have learned to do a test run for placement with lined index cards or graph paper. Especially when I am using a different machine.