@Pier-Silverio0
I find your comment a bit of an exaggeration.
Your profile shows you have only hosted 18 months; and this "grey thingy" was introduced last October following the shooting in Orlinda, California.
However, prior to it, there was 'Pending Verification' in the same colour as 'Request to Book'.
Though 'pending verification' was only for new Guests who did not have a booking record.
The "grey thingy" has replaced it for those who are not fully verified. Still, it seems random as it's not applied to every Guest who has not loaded an ID.
Lastly, as I noted to the CS, it's not simply 'unnecessary', but detrimental to both Hosts & Airbnb, as it blocks the calendar for anyone who is fully verified.