A hidden advantage of the weak no trump?

I've always been a fan of the "weakie".  Usually, that's the 12-14 range (and sometimes a good 11).  I'm also a fan of the ranges that I play when playing precision: 10-12 not vulnerable, 1st/2nd seat; 14-16 otherwise.  The usual advantages espoused for the weak no trump are:

• 1NT is a very descriptive bid and you get to use it more often then when it shows a stronger hand (at matchpoints, it's often the first side to 1NT, especially not-vulnerable, that "wins" the auction);
• Minor suit openings are either good distributional hands or balanced hands with 15+, so we aren't so afraid to open a minor in case it makes it too easy for the opponents to overcall a major;
• The corollary is that 1NT is semi-preemptive, using up the entire one level, thus making it more difficult to intervene.

There are of course a few disadvantages:

• sometimes we "wrong-side" the notrump contract, that's to say we play it the opposite way to most of the other pairs -- this can generate tops, but it also generates bottoms;
• opening 1NT vulnerable and finding partner with a poor hand can be troublesome: we might go down 2 undoubled and still get a zero.

Then there is the de facto advantage at the local bridge club: many opposing pairs either don't know how to handle the weak no trump or they have forgotten to discuss it.  A common error is to think that you can intervene over the weak no trump with weaker hands than you might over a strong notrump.  In fact, the exact opposite is the case.

Today, I found a new advantage.  You can use it for a semi-preemptive 4th-seat opening, in the same way that you might open 2♥ or 2♠ with a six-card suit and a minimum opening bid: you plan to make your contract and you are gambling on the opponents not coming in to the auction.

Clearly, 1NT isn't as good a 4th seat preempt as 2 of a major, but it can be effective.  Take this hand as an example (I held this hand earlier this evening): ♠J3 ♥73 ♦AQ954 ♣KJ97.  We were not-vulnerable versus vulnerable and there were three passes to me.  I can tell you now that passing the hand out would have guaranteed a very good board.  But I wanted to open just in case partner had passed in 2nd seat with 10 or 11 hcp.  Naturally, I would want a diamond lead if the opponents get the bid, but I wasn't planning on letting them get into the auction (I'm short in both majors).  So I decided that a preemptive 1NT was in order.  Call me crazy if you like (yes I know it doesn't have 15 Cansino/Pearson points).  But the local club is a great place to experiment, surely?

The lead was ♦3 and my partner laid down a dummy that was, let's say, a disappointment (in fact, about as bad as it could be on the auction): ♠985 ♥QJ65 ♦J62 ♣QT2.  The bad news was that I was contracted to take 7 tricks in notrump with a K less than average (compared to their K greater than average).  There were actually two good bits of news.  First, with eight spades and 23 hcp between them, the opponents could probably make 3 or 4 spades.  Second, the lead had given me a crucial tempo.

I won RHO's ♦7 with the 9 and proceeded to establish my clubs.  Perhaps the defender with the ♣A would continue the attack on diamonds.  No such luck.  RHO won the trick and of course didn't have any more diamonds.  A spade was led and they fortunately split 4-4.  I pitched my two hearts.  A club was then continued.  I won and played towards dummy's ♦J.  LHO went up with the K and returned... a diamond!  At this point I was able to claim the rest, making my contract.  Had they cashed their two hearts for -100, I think I would still have had a very good board, as they can make 4H or 4S their way.