Like said Aliennaire, you can't travel faster than light, even reaching almost this speed with our standards would be a tremendous, incredible thing, but still much TOO slow for Nostromo for example.
So FTL is needed but is a fictionnal thing, at least for the time being. Space folding..I could have talked about creating wormholes.
They made it because space travel is very long and the crew would probably die of old age without it.
The main problem with not using cryochambers would be consuming food etc..for nothing, they better hypersleep than wasting it. Dying of old age in Alien
films is not an issue but travelling with ships like Nostromo and getting ..years older just for a worktravel is surely one for the crew.