Indeed, which is why Bitwarden should disallow pin-only access for offline vault data altogether. Admittedly, I'm valuing a safe interface for users much more highly than one that is convenient or ergonomic.
That would go against the nature of such software. Let's treat users as adults. There should be warnings. But this is a feature. Users shouldn't be able to eg. select weak crypto algos, there is no additional functionality in that. But setting whatever pin is a convenience, and users should be able to decide what threat vectors they accept.
