It's not really "intelligent" though, as in it's not thinking about what it's doing. What AI will do very well is reproduce jargon, and if it's jargon that we associate with intelligence then it appears intelligent. Academic papers for instance it can do a very convincing job because that format is so repetitive and jargon heavy.

You can do an experiment by asking it to produce a positive review of something niche and academic you're familiar with, then ask it to produce a negative review of the same subject. It will produce convincing dialogue for either scenario, but it does not know which is more true/accurate, and it will come across as a student writing about something they didn't do the reading for.

The "question if humans are [intelligent]" is the more relevant thing here. We're constantly expected to communicate with thoughtlessly reproduced jargon, and many of us can do this very well in a way that gives the impression of intelligent thought. The fact AI can do this, and that people are concerned about how intelligent it appears, is more a reflection on how derivative our notions of intelligence can be in these settings.