Having worked in IT for over 30 years I am somewhat cynical of any form of electronic media - except as a backup
I have seen papyrus scrolls and clay tablets over 4000 years old, but have tapes and backups 10 years old that can't be read. I know that on-line data is possibly secure, but how many websites give up the ghost in a year or 18 months once the developer decides he is bored or the income is not worth the candle
By all means develop your product, but don't expect a huge take-up