The problem is when engineers make presentations instead of writing documentation. The best presentations are when an engineer has written a long page of documentation and walks through it, interspersed with Alt+Tabs to demos of the documented stuff in action.

Too many dysfunctional teams have a culture where engineers make a 1 hour presentation at the end of a multi-week project, upload the ppt and recording somewhere and call it a wrap, without writing a word of searchable and version-controlled documentation.