Exporting paths to Illustrator-problematic

Not a question-just an observation: I ran into a problem when I exported some paths from PS to Illustrator and then treated the paths as if I had just drawn them in Illustrator. That doesn't work, I found. I was setting up a drawing with a lot of branching vessels, each branch smaller than the vessel it had branched off of. When I tried changing the line weight of the successive branching segments, something I do regularly and often in Illustrator, it couldn't be done to the path imported from Photoshop. Try as I might, when I changed the weight of a cut-up segment of the path, the rest of that path, even if it was chopped up and detached, changed as well. I could not disassemble the path to give the segments increasing or decreasing weights of line. I set up a control image next to the path, using the pen tool in Illustrator, and it worked as expected. No problems. So, for me, exporting paths from PS to Illustrator won't see a lot of action in future. What, I wonder, was the original purpose of offering "Export/paths to Illustrator"in the PS File menu? What's the point, if you can't edit the path in Illustrator? I guess the next step will be trying the same experiment with Image Trace, to see if that's any improvement. If I haven't provided enough information here, I can post some examples.