1. It makes the web more annoying and time wasting.
2. I'm a real user and I have to enable JavaScript and run arbitrary programs from untrusted websites to access them. One browser that I use doesn't even support JavaScript (w3m). Fortunately it is unaffected because it doesn't have the string "Mozilla" in its UA and Anubis lets every user without that pass to not hurt legitimate bots like search engine crawlers. As said Anubis is trivially bypassed. The only reason it isn't bypassed is because it's simply too irrelevant to the AI companies.
I empathize, I hate the bloated JS-heavy web and avoid it when I can. I just don't see a better solution. The options for me are: sacrifice some legit users by using Anubis, or sacrifice all users by shutting down my service because I can't afford to serve the bot traffic.