Converters like this are handy for people who don't subscribe to Spotify premium. It's a hassle downloading songs one by one, so this is a helpful tool for people who'd prefer to have a playlist within a minimum amount of time. There are many soundtrack videos with different genres on YouTube that are only waiting to get converted. Have you relied on this for music?
I've used it before but eventually found it inconvenient because the playlists are repetitive, and some songs didn't meet my taste. It can still be helpful if you're after specific audios outside music.
Sometimes, I'm afraid of using converters like these thinking that it might have a virus with it. There are too many ads and pop-ups making it seem that the site doesn't work.
I've used this in the past, and it sure did me well. Youtube converters can help when you can't find particular audio because almost everything is on Youtube, including personal ones.