They are remembered, so it’s only the first time you really have to worry.
But I do think a few rules / intelligent automation wouldn’t go amis. Example:
I (sometimes) buy breakfast, lunch, snacks and coffee from the work canteen. I have separate categories for them (mostly to shame myself to eat breakfast before I leave or to bring in lunch). It’s the same merchant so I need to categorise differently. Some AI (or manual rules) would be able to spot value/time combo and recategorise automagically. That would be nice.