I use it because I have had a chick get its foot caught and broke a toe. I guess until you experience something different you don't fix what isn't broken.
Also when geese hatch they are super floppy and cannot control their long neck and heavy head. I put liner in the bator most especially for their hatch because they lay for so long the wire mesh can be damaging to the face/eyes on the side they are resting on. It can take 8 hours for a goose to get it all together and get that head under control. I choose not to have them flopping on wire flooring.