If 3 ♦ shows this... What had a vulnerable 3 ♠ shown then? xxxxx,xxx,xxxx,x? Well, both 3♦ and 3♠ are strange bid. But 3♠ would be something like 5-3-4-1, and one usefull highcard. A hand with 5 small in a potential thrumph-suit, increases immensely, when it is ascertained, that partner has 4-card support. The weaker the 5-card suit is, the more it goes up in value. I cannot see any other justification for making the "impossible" bids of 3♦ and 3♠.