Actually I read that part of the book but I didn't understand it very well
This bit is important:
Bitcoin scripts have limited complexity and predictable execution times. Script is not a general-purpose language. These limitations ensure that the language cannot be used to create an infinite loop or other form of “logic bomb” that could be embedded in a transaction in a way that causes a denial-of-service attack against the bitcoin network. Remember, every transaction is validated by every full node on the bitcoin network. A limited language prevents the transaction validation mechanism from being used as a vulnerability.
Compare this to Ethereum,
which was persistently attacked in 2016 with denial-of-service attacks.
Another obvious advantage of Bitcoin's model is superior long term scalability. Bitcoin only retains a very limited form of state -- namely, the blockchain and the UTXO set. In Ethereum, by comparison, each block contains a "state root" which stores the entire state of the network -- account nonces, account balances, contract bytecode, contract storage. Ethereum allows for much more complexity and functionality vis-a-vis contract programming and is thus considered "stateful" (while Bitcoin is considered "stateless")
but it comes at great cost:
Eventually, as a node processes every block, we can thus expect the total disk space utilization to be, in computer science terms, roughly O(n*log(n)), where n is the transaction load. In practical terms, the Ethereum blockchain is only 1.3 gigabytes, but the size of the database including all these extra nodes is 10-40 gigabytes.
Ultimately,
this is probably why the number of Ethereum nodes has plummeted during a period where the number of reachable Bitcoin nodes has steadily grown. To counter unsustainable state growth, Ethereum will need to implement schemes like
state rent.
