[dreghgh]

The setting only applies when you enter or edit a value. It doesn't convert values which are already stored in a cell.

[creatonez]

Yeah... a slow burn that is difficult to notice until it's too late.

[dreghgh]

Excel is not designed to waste the time of frequent, experienced users while hand-holding casual users. It's designed to make power users very fast and accurate while possibly confusing casual and new users.