If a keyword is highly demanding in adwords and very competitive niche keyword then how is using that keyword in domain? Will that drive traffic if comp is 90%?
It depends on how many backlinks you got for that domain using that precious keyword as anchor text If you can get thousands of backlinks using your precious keyword as anchor text in linking back to that domain, then that for sure you'll get lots of traffic for your domain will be ranked high up the SERP
Having your target keyword in your domain helps, but it definitely does not guarantee rankings. It just makes things little easier because a higher percentage of your links would use your target keywords as anchor text. You still need as many links as the websites currently ranked for that keyword.