The Cradle first appeared in Avengers: Age Of Ultron as a creation of scientist Helen Cho, designed to help regenerate tissue for human beings. However, Ultron used Loki'sScepter to manipulate Cho into using the device instead to create a humanoid-esque body for him, though in the end, the Avengers interfered and prevented Ultron from using the body.
Instead, of course, they decided to transfer J.A.R.V.I.S.' A.I. into the shell, and after a little help from Thor, the Cradle was struck with lightning which led to the completion of Vision's creation.
It seems unlikely that the Cradle will figure much in the future of the MCU, but given Vision's incredible array of abilities (not to mention his worthiness in being able to pick up Mjolnir), it's tough to argue with the sheer, awe-inspiring power of Cho's device, especially when combined with something as potent as the Mind Gem (which we'll return to later...)