A person onboarding a client catches breaks that have nothing to do with onboarding. Move the whole thing online and that safety net goes with them. Here is what each step toward self-serve quietly hands to your software, told through a one-minute bug I once fixed by hand.
I added one defensive line to a database table and had no evidence it did anything. Two days later I built the incident on purpose. Postgres already keeps every old version of every row, and that still would not have saved me.
A demo is a performance where nothing fails, because in a demo there is no wrong moment. Production is the same feature with one difference: the wrong moment is always available. Two holes I found in my own app, and the tests that catch them.