Certainly it's about so much more than learning the song!

Singing a ballad (to myself) the other day, I realised I'd started using a particular bit of ornamentation to emphasise certain lines. I couldn't immediately think when I'd started doing this, but I eventually traced it back to when I learned Out of the window (a relative of She moved through the fair). That tune included this particular run of notes, which must then have got stuck in my voice memory, & re-emerged in the completely different ballad I was singing the other day.

But the real point of the story is that I had dreadful trouble learning that tune, that run in particular: to begin with my voice just wouldn't do what I was telling it to, and I had to sing it at half speed so as to get the notes right. So there's a case where a few hours of really dogged, mechanical Figaro-Figaro practising resulted in a real extension to my singing technique.