Wrong place do express philosophical concepts… anyway…
There are a lot of different weights of ribbon. Different weaving, different textues, besides different materials. Suggest you simply look at some on your existing equipment. Check what is offered at various sites and sewing shops. Too many to begin to list. It ia all different. Often the difference is simply the style of weaving. Some "ribbon" is more like a tube that has been heated while flattening.
Yeah, that is probably not the best way to make a solid seam, though it cover the seam from abraision and pulling. Unless you leave a LOT of fabric hanging out, it will pull and fray after a few uses. A felled seam or french seam or french felled seam, with slightly wider stitching, would do better, as Jerry siggests. Some fabrics want to be glued, also. Well, cuben isn't really a fabric. Some are heavy enough to simply do as you say. Mesh is often locked in. Some is like screening with minor thread locks at the joints. This seperates easily. SOme untreated nylon pulls loose with even a 1/2" of overhang.
I have a hard time with felled seams. There are basically rolled over and restiched. But, I am a klutz doing this, and, I do not have a good sewing machine capible of doing it. (Overlocker?) I simply seam one side, roll, seam it again. This leaves a loop with the ragged edge inside. Then I flatten/seam it again. Like I say, I am a klutz. I had one tarp split across a panel, between two seams, though. Soo it must be working for me. I can concentrate on accuracy, not rolling just right, pulling slightly to flatten it and seam it simultaneously…silnylon is very slippery. I have managed several tarps and tents, though. Heavier PU coated pack cloth often just needs as you describe. Often the seaming is weaker than the fabric. Stitching too close can ruin it. Stitching to far apart will leave gaps, and/or weaken it. I am NOT a taylor. So, I can only describe what I do…
If it works, it is not ALL bad…