keywords doesn't play that much role in google nowadays as the keywords in the keywords meta tag are ignored by google while indexing and the use of keywords as optimized anchors in on page content is also penalized by in search rankings, so creating original content related to the keyword is the best way to improve page rankings, but anyway you can give keywords in the keywords meta tag for your own reference and content optimization
Keywords are playing key role in SEO But for that should be apply different techniques.Dont need to target keywords through metas keywords because nowdays Google is ingnored metas keywords.. You can target your keywords through title, metas descriptions and as well as content on your wesite.
Keyword is vain of SEO. It plays a major role in SEO and no one can under estimate its role. If you want to ranking site on SE, then place keyword in meta title, description and keyword tag.
When you do off page optimization, also place it in title, description and tag.
Keyword plays important role in Page Ranking. Google uses number of factors to decide page rank like keyword density of same keywords, keywords in url, linking on keywords etc. Thus keyword's role is important in Page ranking.
SEO without poper keyword is just like a body without blood. Page rank depends upon the traffic and traffic depends upon the use of properly optimized and used keywords. If the web content and other on page parameters are suported with proper kws, you wold get better results of SEO practices.