Recently we've been developing an unmanaged package to bundle all our ongoing client metadata in one unit. This is useful when attempting to move stuff between sandboxes before the package goes to production itself.
Different groups of users may want to see the same set of features in different sandboxes. Such as Development, UAT, Training and so on.
My intention was then to deploy this package into production, when ready.
However, Salesforce documentation says
Unmanaged packages should not be used to migrate components from a sandbox to production organization. Instead, use Change Sets.
If we use changesets then we need to remember all the metadata that has been developed. There's no way to bundle changesets. The opportunity for human error is clear.
So why does Salesforce advise against using unmanaged packages as a deployment strategy to production?