"User is required to maintain their own csv files containing daily pricing data for their stocks".
FYI, this is not correct, the daily quotes are automatically retrieved from Yahoo Finance (or others) and the CSV is automatically generated. Doing this manually would be a pure nightmare!
Yes, your mechanism is better (portable, automatic updates, etc.).
How hard would it be to add the Postfolio Slicer stuff to your spreadsheet?
Postfolio Slicer is not well maintained, I would be happy to send you some $$$ if you can integrate what is missing (allocation per sector, support of asset allocation ETF's, missing charts, etc).
FYI, this is not correct, the daily quotes are automatically retrieved from Yahoo Finance (or others) and the CSV is automatically generated. Doing this manually would be a pure nightmare!