I'm not the wagering type of person, but I think that "wagering 4k BTC" doesn't equal to "owning 4k BTC to gamble with".
I think you can own 1 BTC and wager it 4k times - let's assume here you don't win nor lose - and it would correspond to having wagered 4k BTC.
Isn't that obvious? Some people who are new to the gambling world might get confused by such terms, but experienced gamblers like me are fully aware of such terms. Newbies usually go crazy regarding the first deposit bonuses without being aware of the underlying wagering requirements.
It is possible to wager a single satoshi 'n' number of times in order to wager a large amount like 4k BTC.