There’s a lot of different veils to privacy in transactions. There’s the IP record of the user hitting the server that processes their request (it might be you

There’s a lot of different veils to privacy in transactions. There’s the IP record of the user hitting the server that processes their request (it might be your own box if you’re storing the whole chain yourself but most people use thin clients). Then there’s the list of inputs (cryptonote based currencies like monero use ring signatures which provide obfuscation but not binary privacy). Then there’s the list of outputs, which may be able to be linked to inputs revealing the transaction graph (zcash helps solve this with their circuit proving technology, but it’s limited in temporal scope by the fact that there’s a transition between transparent and hidden addresses). Then there’s the amounts of a given transaction (modern cryptocurrencies use range proofs to conceal the amounts but older currencies don’t). To recap, there’s access information like IP, transaction information that can be used to reassemble the transaction graph, and balance information which, again, can be used to reassemble the transaction graph. The broad point is that if you can assemble the transaction graph, any additional information, like a list of known addresses, will severely deprecate the privacy of the entire system. There are potentially ways around this, but they all involve breaking transaction linkability, which is fraught with peril for a variety of reasons (such that no currency has actually achieved this in a meaningful way so far).