I think Reimbursement should not be supported, however Duel Scamming is still Scamming. The reward of the scam might not be refundable but if the proof is concrete, as all Duel Scam reports typically are, the offender should still be banned/punished.
In this way, it is not fully supported however it still is a "hey, fuck off" factor when USD Dueling. Or else, like Nerf and iTemp have been saying, there is unlimited value in USD Dueling to your heart's content. If you win, there's a chance that you get USD. If you lose, you can always just abuse the lack of support and skedaddle. At the same time this change was so insignificant and unannounced that one part of the spectrum would easily have the opportunity to abuse it while they can. People losing might assume they still have to cough up the cash. Aforementioned, there's not a matter of "trustworthiness" in this part of the community anymore because there's nothing to lose by dipping, whereas before high stake duelers typically cared to keep themselves off a ZT/BoS.
Plus, if USD Duels aren't supported then every non-toribash duel related instance should also not be supported. People duel for CSGO Skins and other things just as often.