Also, inserting hidden or misleading links is specifically a no-no for Google Search [0]
Depending on your goals, this may be a pro or a con. I, personally, would like to see a return of "small web" human-centric communities. If there were tools that include anti-scraping, anti-Google (and other large search crawlers) as well as a small web search index for humans to find these sites, this idea becomes a real possibility.
It’s easy to opt out of being indexed by Google.
Exactly. Identifying crawlers like Google, bing aren't the issue. They obey robots.txt, and can easily be blocked by user agent checks. Non-identifying crawlers, which provide humanlike user agents, and which are usually distributed so get around ip-based rate limits, are the main ones that are challenging to deal with.