Looks like there's some confusing wording
I guess its a marketing fine print

I also asked support the same question in response to rohang's inquiry. They told me that everything will be in JPT. At first, I thought that if I bought JPT tokens, they would credit my casino account with $100 bonus in USDT or any currency I want, but support confirmed that the bonus will also be in JPT.
Well actually this is how I'd imagine it will be because otherwise they will be throwing free money to presale buyer. There is no way they are giving away usdt bonus with no wagering requirements just because someone purchase JPT from presale
They also said that you'll be able to swap JPT for other cryptocurrencies once it's available.
Pretty sure this wont be available right at the start the presale deposit is opened.
Imagine buying $1000 worth of JPT in presale then you deposit those $1000 in Jackpotter to get $2000 worth of JPT. Everyone would be rushing to convert it to usdt then withdraw those if conversion is available right from the start