This is really interesting. I've had ideas about accounting as a specialized spreadsheet for a while, both because most people grok spreadsheets naturally and because accountants only want csv files.

In fact I wrote a small script to extract GnuCash transactions into a csv file that can be used as a spreadsheet as a starter point:

https://github.com/dorfsmay/gnucash_general_journal

(There are still issues with this, especially with the way GnuCash converts currencies)

I'll definitely take a look at WeKeep, it might solve some of my issues, and I might just stop my efforts if you got where I was hoping to get.