Literally what's the difference between that and Siri now.

Siri can't understand or pronounce very well.

A few weeks ago Siri via Car Play responded to a text and sent it without me saying a word or radio on, and with the setting where it asks first before sending enabled. It responding "Why?" to a serious text was seriously inconvenient in the moment. I watched it happen in disbelief.

(Edit: Didn't see your last paragraph before writing the response below)

I think there is a distinction between Siri misunderstanding what was said (which you can see/hear), and Siri understanding what you said but hallucinating an answer. In both cases, you strictly have to check the result, but in the first case it's clear that you've been misunderstood.