Why does Katy most of the time sing with her backing studio version vocals when performing live? She can sing but why does she need a backing track anyways?

well i don’t know actually why she sing with her backing, but if it was with me i’ll feel very insecure about singing alive and i’ll use my base vocals. today every thing that you do is used against you, like the “grammy stuff” for example. i think that, even her lives are used against her, to ridicularized her in internet even qhen she sing very well