Image you run an Lightning Node as a merchant and you need to document and process your earnings and spendings with your bookeeping.
Can we have a easy solution here? A start would be to have an LApp/Script that can parse/monitor the channel histories and produces monthly CSV files (text file with comma sperated values) so that you could open it with a excel like data source.
Also to think about is that there maybe BTC/EUR price information is needed to be part of this micro-bookkeeping. A commercial service that comes close is: https://cointracking.info
Why not working with the data store directly? For example all the payments are stored in sqlite3 in c-lightning. this would be easier to interact with than with the json api