A lot of English-speaking visitors don't have accents on their keyboards. As they are learning French, they may already know alternative ways to type accented characters; but shouldn't the site provide some easy way to to so, and document it in the formatting help?
The Mathematics Stack Exchange has facilities for math formulae, for example.
Accents are an integral part of French so I think we must ensure everyone can type them easily. At the very least, if we add no special functionality, I think we could document the existing ways somewhere.