They're lacking of marketing strategy but Betfury is doing well. Gamblers who used to play on their site knows how good their platform is, its just that its not quite popular unlike other casinos who conduct a promo or contest.
Their marketing strategy can maybe be further improved but it is a difficult field where they are playing in. They could launch a bounty/signature campaign, as aioc suggested, as this will create again extra awareness/interest for the site or they can maybe start a partnership with a famous Twitch/youtube streamer...
They hold regular promotions, related to big events such as EURO 2020 or the Olympics where they offer free boxes, extra races, a spin wheel, ...