Double duty: Bike cover & tarp
Bring a bike cover or not? The typical bike cover is big & heavy and serves just one purpose.
But you definitely want a bike cover, especially for leaving the bike parked for a few days while you fly off to Easter Island or wander around Buenos Aires. People are much less likely to molest your ride, either out of curiosity or malice, if it’s covered up.
Solution: A decent size tarp. I found a Thermarest tarp that bundles up in a small sack about 6 by 8 inches. It has a bunch of grommets, so I could secure it to spokes with a couple of carabiners.
Of course it does double duty for camping, or as an emergency lean-to if you get stuck in a nasty rain ... stuff a bike cover won’t do cuz it doesn’t fold out flat & square.