fortis/lenis (lit. 'strong', 'soft') for voiceless/voiced (unaspirated) stops

We had a big go-round about these terms on wordorigins a bit back. Someone kept referring to 'hard' and 'soft' versions of some stop. The proponents of this terminology claimed that it was intuitive and that any child would automatically know which was which, but that 'voiced/unvoiced' would cause confusion. I still have to stop and think when faced with 'hard' and 'soft'.