In an honest form it’s “don’t confuse the crawler.”
In its actual form it makes the web worse. Even if you create a strategy that works Google will eventually shut it down.
It’s an adversarial relationship. The search engines want you to buy ads, not win shelf space.
The organizations that can pull off SEO still do it more to suppress competition. It’s not a low cost way to find customers anymore. It’s keeping people from figuring out you can file your taxes for free.