I am (or was?) a huge Moxie Marlinspike fan, and highly recommend this video[0] of his from Defcon several years ago. It was formative in my understanding of privacy and security.
That said, something here really doesn't add up. Being a huge fan, I took note several years ago of MobileCoin, a cryptocurrency, which listed him on the home page as one of the team.[1] Or, see this Wired article about it[2]. The big selling point, as I remember it, of MobileCoin (per the name) was that it was actually feasible for small clients (i.e. phones) to meaningfully take part in the network. But he's since been scrubbed from the site, as far as I can tell.
MobileCoin was added to Signal, much to the chagrin of HN. And Signal is intimately related to Moxie's work. I had thought that if MobileCoin becomes a thing, then the holders of the originally mined coin would become pretty rich, and I assume that would include Moxie.
So I'm a little confused by how this post fits in. I infer from it that he's new to web3 and crypto in general, but it feels like this isn't the case. (Though "web3" is ambiguous, and I suppose he's referring generally to Ethereum and dApps.) But his main point seems to be that the dominant cryptocurrency isn't suitable for involving light clients, which was the main selling point of MobileCoin.
I just wish it were clear his involvement with MobileCoin, since it feels to me like that could be a pretty significant conflict of interest with regard to Ethereum investigated here and could influence his perspective. For all I know, he answered some questions to the MobileCoin folks and they inflated his involvement. But then that wouldn't really explain how or why it was integrated into Signal.
[0] https://www.youtube.com/watch?v=DoeNbZlxfUM
[1] https://web.archive.org/web/20171216012822/https://www.mobil...
[2] https://www.wired.com/story/mobilecoin-cryptocurrency/