Google's John Mueller posted on Reddit that he agrees, that HTML sitemaps are not worthwhile for SEO purposes. He said "I agree. When it comes to SEO ... for small sites, your site should be crawlable anyway (and if you're using a common CMS, it'll almost always be fine) & for large sites, they're not going to be useful anyway (use sitemaps, use normal cross-linking, check with a crawler of your choice)."...
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Google: HTML Sitemaps Not Worthwhile For SEO Purposes
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