Most of the dramas Hotpot TV lists are indeed actually just official uploads on YouTube they've embedded, but some are actually on Hotpot TV itself, like Well-Intended Love 2 is here (and, despite its About Us page only mentioning the United States, I can get play it in the UK, without a VPN).
I don't think it's particularly like Viki, in as much as Viki doesn't embed videos from another service on its own site.
One could, I suppose, make a rule that only shows hosted by Hotpot TV themselves can be linked to on it. But that would be difficult to enforce, as it would require checking every URL. In defence of including it, however, allowing links to its pages with embedded YouTube videos isn't doing any harm. The purpose of the Services feature, as I understand it, is to make legal options for viewing content easy to find, and linking to Hotpot TV's pages, whether it's their own upload or a YouTube embed, is still doing that.
AsianCrush has been available as a service that links to can be added for a long time now; people have just very rarely added links to it on MDL.
It's I think not been mentioned that AsianCrush also has a YouTube channel with some complete features available in the USA and Canada and complete shorts available worldwide.