Hi I am new to Ethereum (and Blockchain) and am trying to set up testnet using Geth to learn about about the intricacies of Blockchain. So this might be a trivial question: A lot of tutorials out there direct you to add a peer to your node - why do we need peers? What does it help solve? Wouldn't just instantiating multiple nodes (w/ the same genesis file) on the testnet have the same usecase as adding peers? Do you need to be peer nodes on the testnet to transact? If so, why?
Also since each node independently stores the history of transactions on this testnet, how can I access that ledger from a node?
Thanks for answering.