Space exploration comes to mind. What if we decided to send a probe to a nearby star system to explore its exoplanets? Even with superior propulsion technology, the probe might take hundreds of years to get there. Which means we'll need to find a way to keep the probe's computing and communications systems functional for all those years, not to mention maintain compatible systems on Earth. Moreover, once the probe reaches its destination, any command we send will take several years to take effect.