I understand what you mean, and I agree with your point.
What I was trying to emphasize earlier, though, is that many clients make signing and encryption/decryption requests far too frequently, which creates a very poor experience for users relying on bunkers or browser extensions.
For example, the first time you use a client with NIP-17 DMs, your signer may receive hundreds or even thousands of decryption requests. If you are using a bunker, many of those requests may not even reach it because relay rate limits block them first. With a browser extension, meanwhile, the only practical option is often to trust the client and approve all decryption requests at once.