Yes, it is a sticky bonus. From their T&C:

Disciplined 'Sticky Players' make far more  money than 'Grinders'.  Using your example of a $100 Deposit and a $100 Sticky Bonus, and a very conservative Sticky strategy, you would bet 1/4 x (D + B) and play until you either reached a target of 2 x (D + B) or busted.

With this target and this bet size, according to the math, you would be successful in reaching your target 49.6% of the time.  For simplicity, lets call this 50-50.  Say on your 1st one you busted.  You are now -$100 from your pocket.  The next one you hit your target.  Once you hit your target, you grind out the rest of the WR with small, flat bets.  If the WR is $10,000 (typical on something like this), then while grinding you would theoretically lose only $50.  Well, when you hit your target, you had $400 - $100 Sticky Bonus - $100 Deposit, or + $200 profit.  Losing the additional $50 or so grinding leaves you with $150 profit.  So after 2 plays, you're + $50 ahead (- 100 + 150).  Do 6 of these a day, and you make $150 per day.

Then, there are some non-sticky bonuses that you can play 'sticky-style'.  In addition to the money that you made above, you can also keep the bonus.  6 of those types per day give you + $450 per day.  But I don't know if you can find 6 of those per day.

I have played sticky-style only twice.  The first one I hit my target in 4 hands and cashed out then, leaving the bonus, putting $180 in my pocket off a $50 deposit.  The other, I busted in 17 hands, losing my $50 deposit.  So you're finished with them quick.  Plenty of time to go on to the next one.

But it takes a special person to play sticky-style.  I'm not one of them, for I am not comfortable making big bets and knowing that I'm going to lose more than 1/2 the time.  But if you're able to see the big picture and don't mind the small losses, you'll make more money than a grinder with the much bigger wins that you'll get.

don't even think about it,if you break into a sweat with $1 bets think what it's like with £100 bets