We used to say the same sorts of things about LLM prose, music, and image generation. Now just a few years later it can be very difficult to know for sure if something is made by AI or a human. There are still tells, but they are much more subtle and harder to spot, and models are still improving. Mimicing human mouse movement won't be any more of a challenge.
Humans are very inefficient when it comes to navigating the web, but also take actions pretty fast when completing forms. You don't really need advanced ML to see bots spend two seconds to read a full page, then spend 10 seconds just to click two buttons a human would click together in under 2 seconds. The amount of sophistication in bot detection peaks at about 'if user searches 20 queries in less than 5 minutes on our search engine and uses incognito, CAPTCHA them'.
Because of this, perfectly mimicking humans is not a good goal for a bot (as it is the case for AI in music), because they would become very inefficient, at least latency wise (throughput could be engineered around by scraping many unrelated webpages in parallel).