Non has tried bluilding it’s own blockchain with its own currency as for non-blockchain e-commerce system Alibaba been one of the biggest provide no provision for UN-BANKED.
imagine if you wanted to start a grocery store in Japan, you can't tell people to pay you only with Turkish Lira or another currency that you invent. you have to get paid in Japanese Yen.
the internet is not different either. you can't invent a currency only to justify the platform you want to make. the platform has to work with existing currencies and the only existing decentralized currency is bitcoin and people barely use that let alone want to use a new one.
this is exactly why hundreds of others that have done similar thing as you plan (create a token to justify some service or other) have failed.