Auto Text that contains multiple entries with the same root requires you to type the word until there is a distinguishing letter. For example,
incorporated and incorporation
Auto-complete requires you to type until the first letter after the 't' before suggesting an auto-completion rather than presenting you with multiple options say after you had typed 'inco'. Most long words differ at the end - not the beginning, so most of the typing is done before a suggestion pops up. Not helpful. If a list of words that apply were provided (0-9, a-z), you could finish the word with one letter.