FTA: Apple also added Enter to the numeric keypad, although an Enter that almost exclusively did the same thing as Return.

If applications followed the UI guidelines, Enter behaved like Return if enter didn’t make sense in the context and vice versa. Yes, that was mostly (when do you have UI to enter a multi-line text to be processed as a separate unit?) but when it mattered, return started a new line, and enter sent entered text to be processed by the application.

MPW shell was a (?the?) prime example. In its editor, Return started a new line, Enter executed the current selection or, if there was none, line.