I suppose you must know this already if you have done research on alternatives, but there are already a plethora of apps like this — Lifesum, Cal AI, MacroFactor, just to name a few.
Good question! I have added better UX features like the ability to record a voice memo at the end of the day to automate the logging. It would be helpful for someone like a busy professional who is having a hard time to take time out of the day to log his food at every meal... So during his downtime, or before he goes to bed - he can quickly jolt down what he ate and then AI would summarise log it for him.
I'm curious what sets your app apart?