Peter Bex writes:
The "full word" syntax of booleans is totally gratuitous.
They are thought to add a little extra readability, but though implementations must support them, users certainly don't have to use them. R2RS provided them in the forms #!true and #!false, which were dropped in favor of the shorter #t and #f in R3RS.
The WG decided by unanimous consent to take no action on this ticket.