Both of them will exist in different sectors, many people will know about public/open blockchain and it's project while only few people won't even heard about private/closed blockchain.
However, i think private/closed blockchain in small business might be useless.
For me it comes down to trust. These private Blockchains will be manipulated by the banks. { How many people trust banks? } Let's take a
quick example to substantiate my point :
A : Banks/Private Blockchains have sole decision making power over the decision to increase the Coin total. { How many coins there will be }
B : Public Blockchains/Bitcoin rely on the consensus decision of the public to increase the Coin cap. { Less coins = scarcity }
Who would you choose to determine the Coin Cap? A or B
Remember the amount of coins generated in total is one of the factors that would determine the value of your coins over time.
Blockchain is just a technology, it's not always about coins. Many companies have found other usage of blockchain.
The thing about private blockchains, is that they are subject to manipulation,
What are you mean about the subject to manipulation? Where you see it the element will be supporting the manipulation.
Although the node with high trust can decide anything such as changing the blockchain rules. at least we were realizing it is the private blockchain.
