Google Nest Device Access Console now available

On October 28th @BHigg said:

To summarize here:
Make sure that you have the configurations in Karaf (openhab-cli console.) This is done by placing the nestdeviceaccess.cfg and updating the “authorizationToken or refreshToken” (Not both, preference is refreshToken but if you only have an authorizationToken, you can use it…)

Is this correct, should we only configure the refreshtoken? If so, what is the beneift over doing both?
My main issue is that I am intermittently losing the config (any time my web drops, or my openhab reboots)

Thanks for the great work