Why does my cat always want to eat my food instead of hers?

Novelty and smell are doing most of the work here, not a judgment about her own food’s quality. Your plate offers a rotating variety of strong, unfamiliar aromas, warm temperature and the social pull of watching you eat, all of which naturally out-compete a bowl of the same food she sees twice a day. It does not mean her regular food is inadequate. The bigger concern is what she is actually asking for: many common human foods and seasonings are unsafe for cats even in small amounts, so the better fix is a firm no-begging habit rather than sharing bites to quiet her down.