What Are the Security Trade-Offs of Using an SPV Wallet versus a Full Node?

A full node downloads and validates every transaction and block, providing the highest level of security and trustless verification. An SPV wallet, in contrast, only downloads block headers and relies on the honesty of the network to provide the correct Merkle Proofs and longest chain.

The trade-off is convenience for security: SPV wallets are fast and lightweight but are susceptible to a potential attack where a malicious node could feed them a fake, but seemingly valid, Merkle Root and proof. A full node is trustless but resource-intensive.