Currently you can drag a url on to an existing tab, but you can't drag one between tabs and within a tree to open them. It's a small detail but as a long time macOS user, i expect drag and drop to work well in any native app.
Here's an example in safari:
Firefox vertical tabs also support this in the same way. Both FF & safari also support dragging files and urls from other apps on to the tab bar/tree to open them within the browser. Firefox supports it on windows & linux too.
