Most instruments are distinctive in one way or another. Sure there are differences between a baritone and a trombone, but the foundation of their sound is still somewhat related. It’s difficult to find a similar analog for steel drums. They may not get used in every track, or even every album, but steel drums can really add quite a bit to some genres of music.
You can read about this sample library here: http://rekkerd.org/sound-dust-releases-steel-drum-percussion-room-mk2/