CBM’s really aren’t required to survive, but they make day to day things less tedious sometimes, ie, leukocyte breeder keeps hidden health at 100, UPS allows you to power tools that otherwise you need tons of batteries for or have to recharge all the time, internal climate control lets you stay cool/warm in places that otherwise you couldn’t, probability travel lets you go through doors/walls without having to bust or cut them. The only downside to CBM’s is installing them.
Mutations are another story all together, you can change your entire playstyle in any way you want! Want to never sleep, see perfectly at night, be immune to acid, turn into a minotaur/spider/mouse/wolf/other creature etc, etc, etc? Mutation is your game then. It has a lot of other downsides to get to a final, stable, state, and takes a long time to do without turning your character into a deformed mess if you want to do it safely, but it’s totally worth it when you don’t have to sleep anymore.