The new sandbox updates process is really convenient - you can see all the updates a sandbox needs and apply one or more. However it is still very much a manual process to start it. We have a team of engineers and each one of them has to constantly go and trigger the update process manually whenever an update becomes available.

It would be really nice if there was a switch for 'Automatic updates' i.e. whenever it is turned on, the updates are applied automatically during off hours.

Of course if an update fails the engineer would receive an email as it is now and could tend to it on the next day.