Importance of keywords for domain for SEO

keywords are the meat in a spam sandwich.

Now It does not, but if putting it makes it brand-able, easy to remember and understand: Then why not?
As far I have experienced your any action (what ever so called SEO Practices) is meant for ease of searcher and its stakeholders is fair, if you are doing only for search engine then its absolutely a sort of spam or black hat technique.
Google is smart enough it will judge you!
You cant say if your domain has keywords then you will be victim, absolutely not, but you have to be sensible!

No importance.

i read your article,i agree with it,
but i have a question..
how can we make effective our keyword?

Yes its very important in SEO to use keyword of your site as domain name. Means if some of your keyword are same as your domain name its a very effective one. Because when promoting those keywords your site name automatically promoted, if those keywords are found in top automatically your site will be in top of the SERP.

There is no particular rule which says that you must have domain name as a keyword for a site, however it is good for building a brand.