Yes, people do it all the time. The sky doesn't fall if you don't do a coordinated turn, upright or inverted. Flying fields are filled with experienced flyers who don't use a rudder for much more than taxiing.

Once you get upright coordinated turns down, then start trying to coordinate your inverted turns. It won't make you rich and famous nor will it end wars and famines, it will only bring you more personal satisfaction.