However there are many scenarios where it would be infeasible to have a central party. A farmer grows an organic coffee bean in one country and it needs to get to a coffee shop in another country. There are multiple parties and industries involved: the farmer's supplier, the organic certification authorities, the trucking companies that transport the product between farmer/roaster/port/coffee shop, the foreign customs agency, the ocean shipping company, the numerous insurance companies involved, the domestic customs agency, the wholesale distributors, the coffee shops. Throw in the IoT sensors for measuring watering, pesticide use, transport climate, storage climate, and so on that report to the blockchain (which records out-of-tolerance conditions).
Let's say the consumer wants proof the product is organic, how would you do it? What if the beans arrive spoiled, who is responsible? How about if there is an accident, which of the insurance companies is responsible? Who do they pay? What if an outbreak of disease results from the coffee, how would you find the culprit?
The thing is, the world today works. We have records on paper, databases, and huge numbers of people involved in figuring out those questions (though some questions and business models are effectively impossible, like "What if the farmer wants to set the price for a cup of coffee, instead of selling to distributors, how would they do that?").
But these people don't talk to each other. What if there was a trusted business/industrial network of databases that could be integrated into business operations? What new business models, efficiencies, and products would that system enable? That is the promise of blockchain. Bitcoin and cryptocurrencies are silly toys by comparison.
Blockchain is in its infancy. By analogy, if blockchain were the internet, it would be at the stage of dialing into your local BBS by using an acoustic coupler. It is hard to imagine what the world will look like in 30-40 years when industrial/business uses of blockchain are advanced and pervasive.