^ It could be but don't expect that it will have an effect in just a week, to attract players most likely promotions and giveaways and we know forum users are, they usually attract by this strategies. It could be months or a year before you will see a good result and this forum is good to target an audience.
That dumb question, of course, they will add BTC because they are in the crypto gambling community and BTC is the most common, just watch and wait when they will announce and probably the team is quite busy developing their casino.
Betspider may have realized that they need to promote their site in the forum via campaign.
It is true, don't expect that there will be massive change after a week of advertising.
Sometimes, it takes time to see the results. And while doing their campaign, they can add btc and other alts for wider options of the players.
Their staking/dividends feature is in place already. But don't know if they will add btc, what will be the arrangement here.
Also, create contests or programs for the players while doing this campaign, it may add interest to the players to stick for a while.