We'll probably (50% or greater chance) want all the water we can get our hands on. Water makes great rocket fuel and is a critical component of life support systems. Water, having mass, tends to collect in gravity wells.
There's a massive practical difference between Ceres size gravity wells that can be escaped with a half-decent cannon and ones that can't. And I've never heard of people suggesting there might be life on/in Ceres.
Oort Cloud objects as in [0]? Getting to asteroids takes way to long already. Yeah, Oort cloud won't happen unless we have a magical breakthrough in propulsion as depicted in The Expanse. And at that point current intuition around gravity wells will probably not apply anymore as well.