Navigating the expectations of others is a tricky business. We very rarely start at the same place. When we need collective effort to move forward, this becomes a gauntlet that punishes every misstep.
Seamstresses know this all two well. Getting two parts to feel like one is about more than function. What it looks like when it’s all done is just as important, if not more. Chances are, you would get it right given a needle and a thread. It wouldn’t be pretty and it wouldn’t last. More importantly, no-one would buy it.
If you are the customer and it’s not important, sort-of together might work.
Every other time, stitching matters.