The banner is misleading in the current climate because playing Blackjack could result in winnings being confiscated.
They put ALL the emphasis on Blackjack, yet say nothing about slots and big slots winners, this is deceptive marketing as it implies Blackjack is a suitable game to play with the sign-up bonus. As this is an ANIMATED banner, there is plenty of scope to add the rider that the 300 SUB is a slots only offer.
Too many casinos are resorting to psychological deceptions in their marketing strategy, designed by experts in consumer behaviour - whereas the hapless customer stands little chance of seeing what is REALLY going on, as these marketing ploys are designed by experts such that the average consumer will believe what the casino wants them to.
This is also why so many players end up making mistakes and having winnings voided - they read the advertising, and assume it to be the whole deal without thinking to check the small print, which often contradicts parts of the advertising.
The crafty thing about the above banner is that it does not actually SAY that BJ counts, but uses trickery to lure the customer into making the implied connection between the SUB and Blackjack play. The casino can then claim the customer was wholly to blame for not "understanding" the offer, and can demonstrate that they never actually SAID play at BJ was OK.
The ONLY way to avoid being fooled is to ignore the big promises on advertising, but look at all the terms for every offer. In this case, it would show that the 300 bonus has nothing whatsoever to do with the information about Blackjack.
As pickings get poorer, we can expect more trickery from marketing departments, as well as nastier treatment for those who have the cheek to actually WIN from any SUB.