Yeah, but if it was overly hard for her to sing, she could easily change it...she's the writer hahahaha.
Since Harmonium Vanessa's been challenging herself vocally and learning new techniques. I remember she mentioned having a vocal coach while working on Harmonium, and her coach taught her some techniques which she used on songs like C'est La Vie, and you didn't really see anything vocally like that from her before on Be Not Nobody.
I honestly think she's challenging herself as a writer and as a performer by writing more difficult material, I don't think her mistakes are deliberate this time around with Heroes and Thieves though, I just don't think she can quite pull it off. Regardless, I think it's awesome she's forcing herself to grow and mature as an artist in ways that aren't necessarily easy or comfortable for her.