I carry loops of 550 cord and 4 L shaped aluminum tent stakes as part of my poncho-bivy kit. The kid cut up my 550 ridgeline so I've replaced that.

My GHB gear contains the same stuff though the ponchos are Swiss army alpenflage.

I've carried a poncho in addition to raingear and tent and sleeping bag on backpacking trips. Have huddled under it with my buddy as we endured a hailstorm up on a tundra ridge. Have thrown it across pine tree branches so it served as a shelter to eat in when it was raining at dinner time. I've put on my warm clothes and poncho and leaned up against a tree stump to wait out a passing thunderstorm ducking into the poncho to rummage in my pack for a snack. Have worn it as upper covering while hiking in a surprise spring snowstorm. Many uses over the years.

Poncho has been good gear in many circumstances. But the shelter application needs more work on my part to make it anything more than just a waterproof blanket.

One of my scenarios is that I am immobilized for some reason (broken ankle) and have to spend the night out for that reason. Immobility would be a real problem as it impedes choosing a good location, finding insulation and getting a really good poncho setup. Best answer for this is - don't get hurt!