Centralized systems and decentralized systems tend to be faster or slower at dealing with certain types of events. Blockchains are decentralized systems of record keeping. One way to think about a basic blockchain such as bitcoin is that it is an append-only database. Bitcoin can handle approximately seven transactions a second. By comparison, Visa and MasterCard are distributed (but not decentralized) transaction-handling systems that can handle more than 40,000 transactions a second. Blockchain systems continue to increase in speed but typically at with the trade-off of some amount of centralization or restrictions on access. Some PoS systems such as Tendermint or Waves have a theoretical throughput of over 1,000 tx/second but are still far from the peak capacity of their traditional counterparts.