When a new release of BC comes out, developers will typically have to make code updates and deploy them for the next major release. We then have to schedule the upgrade to confirm the code deploys successfully during the upgrade process. This upgrade is set within a time window that can waste time if the upgrade fails especially during a time crunch.

By allow upgrades on demand, developers could deploy there code changes and run the upgrade instantly to check if the upgrade is successful.

Additionally, we have had situations where we make a sandbox from a copy of production and the upgrade date gets set a couple days after the day we made the copy. Sometimes this date is not updatable to be set to the current date which requires us to create support tickets with MS which also takes time.

This idea is specifically for Sandbox environments, but if anyone has any specific reasons for production environments, comment below.