There is a NIP for the client/relay/provider standard https://github.com/nostr-protocol/nips/blob/master/47.md The difference is whats happening on the provider. Alby and LNbits (nwcprovider extension) support defining budgets for each NWC configuration, and allow multiple configs per wallet and overall granular control. Coinos has provided basic support, auto creating NWC connect string for the wallet, but no budget (unlimited spend), no permissions conatraints (full access) and only one for the wallet. In time I anticipate coinos enhancing that capability to bring it up to the standards of other implementations. Subscriptions using NWC for automating periodic pulls should only be configured with those wallets offering granular control.