When i take a swap then it seems i dont have more money. For example i send $100 to trading (since it seems i only can take swaps with money that is there) and then i take a swap, then i only have this swap and a bit less than $100. I dont have the actual money anywhere.

So taking a swap doesnt give you actually the USD you loaned? Its only possible to use them for margin trading? If so then it would be a bit confusing. Giving loans you need actual real money, but taking loans only gives you something virtual.