The best thing about saying 'Finals' is that it very quickly identifies the pedants
At a foreign gliding club some years ago - one of our members used to announce 'Downwind Leg Over' which usually raised a chuckle (it was the only circuit/pattern call we made),most of us through laziness just called 'Downwind'
When I flew power - I most definitely said 'Finals' - purely because it sounds waaaaay cooler than 'Final' - which grammatically sounds plane wrong