I remember being told by a guitar player that 'fretless was dead' in about 1988. I have played one since 1986 (the same one, as it happens). Rock, Blues, Funk, Latin and Jazz, duos, trios, quartets, big bands etc - and all with barely a mwah!. It is an instrument that you make music on just like any other. The music changes, the sounds of the effects added to the instrument changes but the core instrument is no different to the other fretless instruments: double bass, cello, viola and violin.