I’ll go against everyone else so far. Yes, I always take both, and have always used both and been happy I have taken both. Pack rain cover is light and barely takes up any space. I find it’s perfect for light rain where you wouldn’t bother putting a poncho on and being hot and sweaty e.g in misty rain. And I’ll have it on all day on those days that look like it will probably rain or the on/off rain that is so common in Spain. It also buys you time while deciding, if you really want to or need to put the poncho on. In super heavy all day rain (e.g. 3 weeks straight in Nov 2019), having both on at the same time gave me peace of mind that I had the best chance of having dry stuff at the end of the day, waterproofing gives up on everything at some point.