A demo that looks finished is not the same as a system someone else can run on a Tuesday.
Handover is the part most builds skip. Access, logging, a short note on what to do when it fails, and a person who still owns the exceptions.
If that work is missing, the thing is live in name only. It sits in a folder until the person who built it is on holiday.
We treat handover as part of the product, not as a slide at the end.