Why are you addressing it as scam when Duelbits has given you the option to receive your withdrawal by completing the KYC verification? You made a deposit of 1119.82$ in BTC on 2:31 PM of 28th March. Then you requested for a withdrawal of 1118$ in LTC after 20 minutes. It is reasonable to request for identity verification in such situation. The AML and KYC terms of Duelbits state that
This is absolutely the reason why duelbits ask him fulfill KYC and it is reasonable for any casino to do the same because his action is high likely being suspected as suspicious activity.
I do believe that he did not wager after making the deposit, he made the deposit-wait for 20 minutes then try to withdraw it.
I have no idea what is his main intention for this action, is he trying to us duelbits as a mixer?
2- They can ask me wager the funds as some sites do
With this statement, I assume that you are an experienced gambler but why didn't wager it before it is happening to you?
I think duelbits will not ask you to complete KYC if you wager enough money after your deposit.
You are asked to do KYC because your action is considered as suspicious, and I'm sure you will get the same experience in all casino.