Using libcanberra has some advantages. It does not rely on the oxygen sound being present, which is probably not the case in a non-Plasma install. Instead it uses the freedesktop.org sound theme spec to find an appropriate sound. This also takes into account the users configured sound theme. It also promises better latency than the QtMutimedia player.
In theory this could also work on Windows and macOS, but I haven't tested it and would like to have that confirmed before I kill the QtMultimedia codepath.
An open question is what to do with the configurable sound option. In theory we could pass the configured sound file name to canberra, but I'm inclined to kill that option since IMO it does not provide much value