On the finesse worm and wire, I think both. 20 lb Flurocarbon might be difficult for the fish to see, but it would still overpower the finesse bait and ruin a big part of what makes it attractive. With a big freaking piece of wire attached, you be hard pressed to catch pressured fish for sure.
Most lures allow some leeway in fishing line used, but there is a place for 6 thru 20 lb in my fishing. Others can use what they please when they please. I spend a lot of time and energy trying to be a better fisherman, but it's nothing to get mad about.