many years ago, I asked why a precision natural 2♣ is alertable, but an artificial strong 2♣ is not. people looked at me like I was from nuthouse.
IMHO, it causes more inconsistency and chaos if alertablities are based on familiarity instead of intrinsic bridge logic.
The way ...
Holding ♠ QJxx ♥ xx ♦ Qxx ♣ AKQT, I couldn't see why 4N would be any good, whatever partner has with that 4♦. it is wrong sided, more or less, only works when your side having 10 tricks on top ...
it's a lucky slam. you are not allowed to be lucky after that tank.
West would probably argue he always gonna to bid over 3N. but if ♥ J were in ♣, slam looks silly, not to mention East could have had only 4 trumps.
As dummy has ♦ Q, I would expect South giving count on ♦ K, and it should solve North's problem.
That said, seems trying to cash 2nd ♦ was a mistake. Because ♦ 2 indicates South could not have a doubleton. If East had ♦ Jx, seems he couldn ...