Your screenshot is taken out of context (and yet you can see the messages themselves are not the main point of Satohi's post here).
This reply is in regards to another bitcoin talk user's suggestion to use encryption built into Bitcoin to enable short messages attached to transactions. He compares these to payment titles in traditional finance.
Satoshi's reply displays his concerns in regards to privacy – see the part of the message you specifically highlight: "...permanently recorded PLAINTEXT messages..."
For more context on this topic see another Satoshi's comment – attaching a screenshot.
Link to full thread: https://bitcointalk.org/index.php?topic=1545
Link to Satoshi's comment on ECDSA encryption inability: https://bitcointalk.org/index.php?topic=30.msg1169#msg1169
I admit I have not read every single one of satoshis forum posts. I concede that the main point is privacy. He does also say very clearly he thinks messages belong on a parallel network instead.
I am curious though. Do you really think 100kb image files on chain will be good for bitcoin?
Thank you for this information, seriously. Always trying to learn more.
I do not think arbitrary files belong on the blockchain, but I do not know the best solution here is.
I do not think filters will work well, I do not think OP_RETURN increase is the best way forward either.
Decentralized monetary protocol is a super complex thing, and debates like these - Block Size War being another great example - are inevitable.
We are yet to figure out the best way forward, and I believe we will figure it out collectively. We just need more time and data. We need to carefully consider second order effects that any decision might cause.
