Onchain Bitcoin is public, and Lightning Channels are public, but, like, you can't collect analytics on which IP address submitted a Bitcoin transaction, or a paid a Lightning invoice. That data is simply not recorded. But, as far as I understand it, every Spark transaction begins with a TCP/IP request to a centralized server, and that server can record user activity, and not only that, but it's being recorded by a big, regulated financial services company. Like Paypal, Coinbase, whatever. It's not decentralized, like Nostr is decentralized, or Lightning, or Bitcoin. Maybe that's fine, it's just that, this will be a risk if a huge number of wallets use it as a back-end, and those wallets position themselves as somehow safe to use from a privacy standpoint. Maybe that won't happen and I'm overthinking this.