Numbers wise, sure, there are certainly more invasive species out there.

The trick with Kudzu is that, unlike ligustrum sinense, it invades in a much more literal sense, covering both other plants and the ground itself as far as it can. It 'universally' impedes the growth of other plants, and arguably makes terrain less traversal (if only because it covers what's underneath).

It may not be an ecological danger, but it can be a pain. Yes, other vines can grow as quickly, but most of them have smaller leaves and less propensity to carpet entire areas. I think the visual impact may make it feel more impactful and lend to its mythologization.

I saw it do some impressive stuff. These articles pop up, from time to time, but you need to see it in action.