Thanks for the reply. But if you look at big sites like Yelp and yellowpages etc their html and xml sitemaps look massively different. They use an index xml sitemap to point to a straightforward list of sitemaps with 50 K links per sitemap, whereas the html sitemaps are much more based on intuitive navigation.
I understand that sitemaps are useful, my point is just that given that an exhaustive xml sitemap is already in place, won't an html sitemap be redundant for indexing purposes? Is there anything wrong in using an xml sitemap strictly to aid indexing/crawling, and use an html sitemap strictly for usability?