For example, I do 99% of my grocery shopping at about 3 shops. So if the data was available it would be trivial to write a script which totals the amount I have spent that month on groceries and graph that against previous months.
The only way I can do this is to go into the banks website and manually add these figures together every month. This just seems like a terrible inefficient way to do it.
It would be great to be able to just go through my bank statement and say "oh , Steam. That's an entertainment expense, so in future put that into a bucket called 'entertainment' so I can see what that is as a percentage and track how it changes". I could also see blips in things like quarterly expenses (utility bills etc) and plan for them accordingly.
What would be truly awesome would be to apply some stats and ML to it and say "If I make large purchase X for £Y in August what is the increase in probability that I will fall into arrears come Christmas based on my historical spending patterns"
If I was feeling cynical I might think that banks don't really want me to plan my personal finances too well. They would rather I mess it up now and again and have to apply for credit.