user21738: I am reading this and now wondering why the blockchain isn't just implemented as a Merkle tree, or the reverse, why you can't just have a single data structure (i.e. a transaction chain) instead of the block chain with nested Merkle tree of transactions.

user63872: A bitcoin full node independently validates the history of the network. To do so, it must validate each block in sequence (which includes all transactions in each block). 
A merkle tree provides a cryptographic commitment to some data, but does not hold that data itself (it just holds hashes of the data). So a merkle tree alone is insufficient to validate the history of the network. Nodes need block and transaction data to do so, not just the merkle tree commitment. 

21738: <p>I am reading <a href="https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch09.asciidoc#mining" rel="nofollow noreferrer">this</a> and now wondering why the blockchain isn't just implemented as a Merkle tree, or the reverse, why you can't just have a single data structure (i.e. a transaction chain) instead of the block chain with nested Merkle tree of transactions.</p>
 63872: <p>A bitcoin full node independently validates the history of the network. To do so, it must validate each block in sequence (which includes all transactions in each block). </p>

<p>A merkle tree provides a cryptographic commitment to some data, but does not hold that data itself (it just holds hashes of the data). So a merkle tree alone is insufficient to validate the history of the network. Nodes need block and transaction data to do so, not just the merkle tree commitment. </p>
