Yes, websites are for humans. But, for better or worse, humans live in a world that is driven by advertising, media, and funny concepts like SEO. If you want to stand out, you have to not only provide a great website (that works for humans) but you have to tell humans about it. Sometimes that means advertising, or doing a few things to make your site more easily crawled by bots. This is ok, and a natural part of a website's life. Most businesses have a marketing department, or at least a marketing budget. If you want your ideas to spread, you need to consider what to do to get people to show up.
Sure, although I think making your websites machine-readable with schema.org or sitemaps is worthwhile. Right now those are just cool addons (like star ratings visible on SERP, or cooking recipes aggregators) but you never know who might do something really interesting when given access to information that is easy to parse.
BTW What is the share of robot traffic to your website? I'm guessing pretty high.
