It's very useful to me to be able to find vocal performances on the internet. I can very slowly decode pitch from dots, but timing totally eludes me without an exemplar - although fortunately in folk music one is not slavishly tied to previous versions.

However things normally done in harmony may be buggers for finding the correct lead line without dots. My late wife Jacqui Walker was useful for that, but I'd need a Ouija board to get help from her now.

And sometimes the accompaniment can obscure things. I'm STILL struggling with "Monster Science" aka "Lord of Steam and Iron" as performed by John Kirkpatrick despite Will Fly having kindly sent me the chords.    Similarly (absent Will Fly) Stockholm Tar as performed by the Spinners.

And for folk(ish) song the dots may be hard to come by.