Tell me, will you have some kind of reserve fund? If the project that conducted crowdfounding on ARIZN platform wants to take money in a fiat currency. For example, in dollars. Where will you get them? I think that the problem of the liquidity provider will be acute.
I believe that the token that will be provided will just become your proof of support for the project. Yes of course the project will need fiat money so they can spend it in real life. I think the process will be like this, A project proponent use ARIZN platform to source out funding for his project. People may contribute fiat money or crypto currencies, ARIZN will provide a smart contract for each funder and a token in exchange for their support. The token really has no value yet. Money or crypto currencies will go to the project owner's account. I think this will be the process on funding a project.
I guess the OP should refer first on the one-pager of Arizn because it simply discuss how investor and founder interact in the ecosystem of Arizn. Fiat currency investment is not a barrier to invest in a project you want to fund and I think there are reserve fund but in case of fiat, it is different from cryptocurrency raised funds.