I usually use octane live preview for stills insted of final render.

for example, I need this option to send some quick renders for the customer.JimStar wrote:What is the usecase for it?..
Interactive rendering session is by definition volatile - you almost always change something when it's active, it is its main purpose, to watch the scene changes... If you close the interactive window - there will be almost certainly something changed in the scene before opening it the second time... If not - what's the point of closing it at all?
Plus, the interactive session's ideology - is to be simple to run. It will be broken by the overhead of saving the session every time you close it plus asking you every time by annoying dialog before opening the interactive window: "Do you want to use the saved session?"...
Too much harm for the feature that supposed to be quick and interactive preview, and is not supposed to be used for final rendering...