@mahgister
She can sing Bach, Verdi, Shubert or Schumann or any spirituals and would had sing jazz over any other female singer...
A matter of taste, surely.
How many Jazz fans enjoy Jazz sung with a classical vibrato?
Sarah Vaughan is perhaps the most "operatic" of Jazz singers but she still doesn’t sound like an opera singer.
I’ve never enjoyed Joan Baez or more recently, Rhiannon Giddens, precisely due to their vibrato. Giddens trained as an opera singer -- not sure where Baez acquired it, but to my ear, at least, it sounds very out of place in the Folk genre.
Perhaps I’m biased towards preserving a certain integrity when it comes to musical genres. No doubt, there are others who are all for breaking down the characteristics that traditionally define genres and fusing them into something new.
I can’t imagine classical guitar played with a Blues-style vibrato, for example but perhaps there are those who would find it appealing.
More to the OP’s point, as music is a language that operates on multiple levels, simultaneously, I don’t find it surprising that we may be strongly affected by a certain piece without necessarily being able to discern why or, that we may not be able to even name the particular/combination of emotions, it evokes.
A composer (presumably) is intimately familiar with how various factors such as time signature, key, intervals, timbre, dissonance/consonance, density, etc. are likely to impact a listener. As to why-- well, that’s a more difficult question.