I think anyone that have been here before with their active email will get this for sure. So if you are not getting it, means that you are not yet played it here. And may be you are still active according to their terms. We never know how they support team manage to get it done but yes, most of the inactive account will get this 50k satoshi. I also got the email but unfortunately I can't use it
I got the same welcome bonus 2-3 years ago but it's not through their email and it was an pm from one of the admins. Maybe we're in their list of top users that wagered and reached a certain amount because back then I used to play almost every day and remember having like 2-5btc on my overall wagers before I went inactive.
Yes, in the last few years ago they sure giving some amount through PM because it is only small number to be PMed and much of them are in forum so it is better sending them here(I got once as well). But in the current time, there is tons of people gathering on their site. So email is much better thing to spread, plus it is easier for people to notice it since nowadays people are checking their emails everytime, especially when they are in crypto industry