Issues faced by blockchain

Decentralized systems are great in many aspects, but they are inherently disadvantaged versus centralized systems in the important aspects of scalability and governance. Running consensus among all nodes on the network just takes too much time and energy. Contrast this with a network with just one central server. Surely it will run faster? But we have already discussed the disadvantage of the central server model: it has a central point of failure. Therefore, there is a trade-off between scalability and speed on one hand, and security on the other hand.

Scalability

Blockchains, at present, are notoriously slow compared to centralized payment processing networks, such as Visa, Mastercard, and PayPal...