I think that we should have a global virtual marketplace for cryptocurrencies without any intermediaries. This would lower the costs of transactions and decentralize the market. What do you think? Is that possible? What are the benefits?
The question itself is self contradictory. Global marketplace and decentralization doesn't really go along. There has to be a platform which needs to be run by an authority to maintain the daily operations. Otherwise, it will become the heaven for scammers!
We already have a lot of exchanges in the market where the fees are quite low which won't pinch your pocket! Also we have platforms like localbitcoins and paxful for crypto to fiat transactions. These are not decentralized but does the required job smoothly!