What makes managing receipts so annoying?

One of my friends has been building this receipt organizer app for a while and after he showed it to me I thought it was actually pretty useful.

Basically you just scan receipts and it stores/organizes everything digitally instead of having random paper receipts, screenshots, emails, and transactions all over the place. It can also sort spending into categories and makes old purchases easier to find later.

I didn’t think much of it at first, but after using it a bit I realized how annoying receipt management normally is.

So now I’m curious what other people think about apps like this and what features would actually make them worth using long term.
I can show yall plus just wanted to help him out dm me if you need to ask questions about it will hopefullt itll chear him up