So here is my point ? Gamblers who are active on Twitter will get those promotions. Right:

What was better that they should have posted the giveaways on the website and the gamblers who were more active on Duelbits could avail of those discounts.
I know there may be many people who are not playing at duelbits actively. By announcing the giveaways only on Twitter means that they want more inactive or new people to join their site.
Don't worry, those who are active in playing in duelbits get bonuses from other events like an exclusive bonus, happy hour and others which is clearly bigger than on Twitter
You might know why they also need to do it on Twitter, obviously they want to get new users through the bonuses given they will get new experiences and there is a possibility of being an active player in duelbits this is a general marketing carried out by any casino, casino will not survive if only relying on existing players so they need new users.