This is not quite right. A wallet is not the same as a node, it never really was. A wallet is three things: a key manager, a transaction signer, and a type of blockchain explorer (shows your keys' validated onchain transactions). A node is a repository of the blockchain. When it receives transactions from the bitcoin network, it validates those transactions according to the rules encoded in the software. Any blocks that are received that don't follow the rules aren't included in the blockchain assembled and validated by the software.

When you receive bitcoin during commerce, you will not settle the debt from the exchange unless you have verified the received bitcoin is on the blockchain. This is the moment where you "assay" the bitcoin. You do this by using a wallet you trust that accesses a node you trust. There are many wallets available and there are thousands of public nodes available for you to do this. You can also keep the network honest by running your own node (inexpensively) and confirm other nodes in the network are behaving properly, but the average person has the power to know whether their received bitcoin is what they require. Once you hold bitcoin, there is no way for anyone to change it. If someone forks bitcoin, you have the power to sell the invalid bitcoin while not touching your real bitcoin. It's the holder and the recipient of bitcoin that decides which codebase and which blockchain is the real bitcoin.