In future, when the project will be done, can we buy arts with fiat or only with your tokens?
It depends on which exchanges Artpro will be trading in the future. There are those where you can sell cryptocurrency for fiat as well.
Or you can buy art for a long time. These are also very liquid assets)
because you will have many options how to spend your tokens
Well, as an option, you can do so. Let's see how the project will work in the future and what services will be provided to end users.