What is AC used for as is without being rectified into DC first, if anything?
transformers AC electric motors heating elements in transformers to step up/down the voltage ( this provides much effective, less cost way to step up/down the voltage than using a DC step up/down method) for widly used AC motors (AC motors for mechanical putput and synchronous motors used as synchronous condensors) and it is much efficient to produce AC voltage than DC voltage in large amounts
Most Appliances at home are designed to to take AC direct without rectification.
AC is the simplest way to distribute electricity, especially over long distances. If DC is needed, as in electronics, the AC is easily rectified. The vast majority of motor driven appliances have AC motors, and heating elements (stoves, water heaters etc.), work directly on AC just like they would on DC.
