Those are aerial roots, some plants produce lots of them, mostly many types of vines. Yes you could start a cutting easy from that, maybe some rich moist well draining potting soil (cactus soil) would be better than water. Jade plants don't like soggy soil at all, they can rot. They like the soil just to be slightly moist and also like the soil to dry out slightly between waterings. They also like lots of sun, like a south window. And try carefully not to break the aerial roots when planting.

if i am not mistaken.. jade will root from single leafs ...

or a cut just below the roots..

or any piece of the stem ...

about the only way to kill it.. as noted.. too much water

there are reasons this is one successful house plant.. in zones where the forced air furnace blows for 4 months of the year ... because it likes it dry ...

ken