I like how cryptocurrencies were launched as an alternative to central banking, wresting control of money away from the government and big banks. An open and level playing field that would democratize how people transact financially with each other. And then the first thing the early adopters did was recreate the flawed financial institutions that surround "real" money so that they could pretend to be Gordon Gekko an…
Exchanges use off-chain transactions. When you see a transaction on the block chain, it's very unlikely to be a settlement between two exchange customers because it's far more efficient for the exchange to settle on its own private ledger.
On-chain Bitcoin transactions incur fees. Aside from a group launching an attack on Bitcoin, there's little return for the cost of spamming the block chain.