Why the board appears to be so dead now?
Because the site is getting close to dead as well IMO, last bet was more than 10 days ago. It seems that after they reduced the winning payout from x16 to x10, people started to leave the site. As long as I remember, the winning payout was x16 which had low house edge, but now it is x10 only which means higher house edge. Other than that, the game itself is not so popular although it is a provably fair game. Gamblers prefers to play on dice game if they want to get x10 payout, which is simple and does not require fee for every bet they make.
I think the reason why these types of sites close is because these days many other gambling sites started accepting anonymous coins like XMR, DASH and ZEC.
A few years ago the on-chain betting websites had more success for a few reasons. One of the reasons was that the fees were much cheaper and people didn't mind paying 1000 Sats to send a transaction. And back then BTC was in fully domination pretty much so people had no choice but to use it.
So if someone wanted privacy and didn't want to expose their IP address or have to create an account and expose their email address they would use the on-chain bet websites.
However right now with all the viruses and people keeping all their BTC on cold storage or electrum, its alot of work just to send a transaction. Hence most people probably for privacy just use a VPN and use a coin like XMR.
This is the reason why sites like this are slowly dying off.