While I like non custodial and open source solutions, I also think it's inevitable to have a client that's closed source and profit driven. Why? Mainly because Nostr is open and allows this. I don't think it's a threat to Nostr. I think it's perfectly acceptable for some users.

For example, Twitter could implement Nostr. They'd implement a customized relay and a customized client. They'd manage user relays and user keys for them. (Essentially what ZBD is doing.) Then, if we want to interact with those users, we'd add the Twitter relay. I honestly think at some point down the road, this will happen.

I may not sure it, you may not use it, but that doesn't mean the client won't serve a purpose for some. I don't think they're a threat because in the end, the free market will decide. And if I'm right, the free market will choose open source.

I view them as a Trojan horse. The same as I view custodial solutions for Bitcoin. Give users a taste of freedom then show them they can have even more!