Align actually should refer to the content inside the box, and float is needed to position the box itself (if the pattern for other objects is followed). But I don't see align having any effect in this plugin in 2.0, now that you mention it. This is probably a bug, and I'll report it.
tikipedia.css regarding these box details didn't change from 1.9 to 2.0. I didn't compare the plugin file versions, but if the plugin has changed (and apparently it has), the reason might be to have better compliance with standards. I think "align" as applied as a tag is deprecated (supposed to be replaced by a newer method). But in the DIV plugin (and probably also in BOX), the "align" parameter is used as the text-align property, which is good CSS practice, along with float to control its position relative to its parent.