- the misspelling maté puts the emphasis on the wrong syllable,
- the misspelling maté is a different word, and
- maté is first person preterit form, I killed. Okay, two and three are arguably the same objection.
The discussion at the Wikipedia maté page saved me from making a change to the page that someone would have to back out of later. Someone pointed out that the spelling is incorrect, but someone else pointed out that the spelling is the one used by the gnome project, and it's not Wikipedia's place to correct the spelling of a project name, but rather to use it as-is. I agree, but I will not be using the misspelling.