How is a DAG different from other distributed ledger technologies?
Practical differences between a DAG and a DLT typically include greater scalability and lower transaction fees for a DAG. They offer much higher validation speeds. In fact, whereas Bitcoin-style blockchain slows down as traffic increases.
A blockchain is a long list of blocks, so in order to find the last transaction, you need to search backwards through the whole block (this is time-consuming). To minimize this issue, a database searches for the unspent output from bitcoin transactions (UTXO) instead.
There is no mining on DAGs and therefore no need to incentivise miners through mining reward systems and thus, no need to charge users high transaction fees. No mining also means no mining equipment, the sort that you’ve undoubtedly heard uses more energy than entire nations.
With little or no transaction fees, DAGs can be used in situations where blockchain would not be feasible. A prime example is micro or nano-transactions between devices and sensors. DAGs however often contain a fee to reduce the spam and to control the supply of money.