It's not going to hurt, but it might look dumb. Generally if you're going after a competitive keyword I'm assuming you are going to be offering something of value. If it's just for a MFA site, then just get the keyword1 domain.

But let's assume you want to sell a product on the site. Would people be more likely to buy from autoinsurance 1.com or geico .com

Sometimes branding is better. If you can work the keyword into the brand, then great.

How about this - autoinsurancehq .com or autoinsuranceauthority .com

or whatever.

I saw many websites..who use the keywords as a domain name.I guess,its sometime help website and also keywords ranking..

According to personal experience, keyword + numbers is a good choice when the EMD has been taken, but just like packerfan said, meaningless numbers might a little dumb, so you can try some numbers meaningful. For example, BMW was founded in 1916, so BMW1916.com might be better than BMW9263.com.

Where is any proof that having kw in domain ...................that by itself.............if its NOT an EMD

means anything

kw in URL
sure...............thats why millions of sites rank high and they make sure to put
www.domain.com/keyword.html

but I am also guilty of focusing on HOW CAN I PUT THIS KW in The DOMAIN if the EMD is not available

IMO thats a common area of focus for newbies
I do not think google gives any additional benefit to kw in the domain.........UNLESS its an EMD

start adding numbers? or words to the EMD.....it becomes meaningless SEO wise IMO

According to me it wont hurt your ranking, you need to put a genuine and unique content on your website.l you need to create a blog and update it on daily basis.
Try to get backlinks from authoritative websites so you can get some online reputation

Partial EMD's do help. I just got a hyphenated EMD with 30,000 exact searches/ $4 CPC to the second page in less than a week. BUT if your going after a competitive keyword, you are far better off getting an aged domain.

If you don't know what it takes/don't have resources to get a page one position, then don't even bother and dig a little deeper into long tail derivatives.