These widgets are useless and only trigger extra $updateViews.
The only reason we had them was to support ng:change on these widgets,
but since there are no bindings present in these cases it doesn't make
sense to support ng:change here. It's likely just a leftover from
getangular.com
Breaking change: ng:change for input[button], input[submit], input[reset], input[image]
and button widgets is not supported any more