It's a step in the right direction, but it still reveals the recipient and doesn't do key rotation, so all your message history and future messages are revealed if your main Nostr key is ever compromised. It's a tradeoff between security and availability. I'd personally choose Signal-style key rotation. 

 If you want to use multiple Nostr clients for the same double ratchet or MLS chats, they can technically be different members of a group. MLS would handle that better especially as groups get larger and numerous.