So both spin off and instantiation option do the same...The only difference is in instantiation there are many ways to determine when the child case should start processing. Apart from this in spin off only one operator can work at a time. what about instantiation option?
A spin-off flow is a process that runs in parallel with the calling process, or parent flow. Spin-off flows can work on the same case as the parent flow or they can work on a different case, based on the context that you provide.