The larger the depth of field, the more of an issue it could be - so small apertures and sensors would pronounce it. I've yet to see in on my M43 camera though.
I really wouldn't want to flush wax through my kitchen drain.
I'd rather chuck it in a plastic container and discard the solidified wax when it's cooled off.
I used to feel the same way.
I worked for a couple of years as an apprentice commercial photographer and we shot mostly 40mp Phase One digital medium format and 24mp Canon 5d Mark II.
These days I'm more than happy with 16mp M43 and transferring the photos to my iphone or printing 13x18 cm prints.
Wide black walls really suit the build. Could do with some bdhu though.