Yes, actually, he uses the deck that is the most difficult to farm among Legendary Duelists Lvl 40. By using the event exlusive Destiny Board of Doom, Ectoplasmer, and Soul Exchange, he never allows you to stall turns. Additionally he has Sphere Kuriboh and Enemy Controller to defend himslef from your final attack to aim to achieve Over 5,000 or 9,000 Damage.
How about Lvl 50?
Lvl 50 is easier relative to Lvl 40 since he has no Ectoplasmer and Sould Exchange. However, farming Lvl 50 will be still depending on your luck due to the effect of Dark Master - Zorc.
Should I farm Lvl 30 instead?
If you just aim to earn points:
It depends on your objectvie, but if you just want to earn event points, defeating Yami Bakura Lvl 30 with higher Duel Assessment seems to be reasonable.
Yami Bakura Lvl 30
6000 x7 x2 =42,000 x 2(20 Dice x2) = 84,000
7000 x7 x2 =49,000 x 2(20 Dice x2) = 98,000
Yami Bakura Lvl 40
2000 x18 x1 (40 Dice) =36,000
3000 x18 x1 (40 Dice) =54,000
5000 x18 x1 (40 Dice) =90,000
5500 x18 x1 (40 Dice) =99,000
6000 x18 x1 (40 Dice) =108,000
4 of event card do not seems to be useful.
Unlocked Yami Bakura
This is the only one you obviously have to obtain during the event.
Card sleeve & playmat
Those accessoreis looks really cool, although these accessories do not affect your duel.
Gold, Gem, and Jewel
The total amount of those items you can earn during the event is surprising.
I honestly don't think he worth it at all there are some card that i think you can do some tricky stuff with but honestly it there are much better stuff in boxes and the other legendary duelist. If you can get dark necrofear i would absolutely farm some more but they're isn't that chance. Very very disappointing
before he came out his skills themed were reliant on the graveyard style of play, but his cards except one rely on that anyway. This event is a let down and I only farm him because he currently is the only one as a DA reward dropping the SR orbs and as a F2P I desperately need those
Continue farming him once you get all the SR orbs as rewards, but on lvl 40, since there are more chances to get his cards, therefor allowing you to convert them into even more SR orbs
Well, if you make the math, Yami Bakura lvl. 40 costs DOUBLE the dices as lvl. 30. So if we follow your chart, assuming the Dices to Points radio.
6000 x7 =42,000 x 2 = 84,000
7000 x7 =49,000 x 2 = 98,000
2000 x18 =36,000
3000 x18 =54,000
Maybe I'm doing something wrong, but I've tried that deck several times and haven't won once. I think I'll stick with my lvl 30 farming deck, which has been able to get around 9K consistently. 2 rounds of that isn't much lower than what you got for the same amount of dice, and it's a lot easier IMO.