Relationship between html autocomplete and aria-autocomplete

I am trying to understand if there is any meaningful relationship or 
conflict between autocomplete and aria-autocomplete.

I see in the HTML AAM this note: the ARIA attribute and the HTML attribute 
have disparate features. 

Is that really saying that there is no problem with applying both to the 
same element with different values because they are serving different 
purposes?

For example, <input role="combobox" type="text" autocomplete="off" 
aria-autocomplete="list">
to prevent browser from making suggestions on an input for which you are 
scripting a suggestion list?

Matt King
IBM Senior Technical Staff Member
I/T Chief Accessibility Strategist
IBM BT/CIO - Global Workforce and Web Process Enablement 
Phone: (503) 578-2329, Tie line: 731-7398
mattking@us.ibm.com