Why cant we say like we do for doing sacrifices on Shabat that this verse says that even though you can't do normal burning on Yom Tov [the festival] but in case of burning leavened bread- chametz there is an exception.
Because then we would have to split up the verse "make to rest". If the verse would only say burn unleavened bread only for need, then everything would be fine. But that can't be what the verse means. The main intention is to burn the bread not for any need but rather to get rid of it.