Wild hand with many results.

The advantage in duplicate of 3NT over 4 of a major.

Also the difficulty caused by pre-empts.

7 card suit and 6-10 points, many will pre-empt with 3♦, even if only J high. W may be tempted to double or bid 3♥  with only 10HCPs, but vulnerable, probably not a good idea. Those that over call 3♥  and end up in 4♥ that goes off. Those that double will end up in 3NT.

If W passes E has a difficult call.

If S passes, W may open 1♥ , E will respond 3NT if that shows a balanced 13-15 finding the best contract.

Only one table ended up at the optimum contract of 4♦ doubled.