Emergency Money

I am wondering shall I cancel one of my credit cards. I am having three credit cards right now. Two are Average Credit Credit Cards which I will continue renew. But another one that I wish to cancel, I am enjoying highest credit limit compare to the other two. As what I am concern, I keep this as my emergency money facility. I no need to pay single cent if I am not using the credit. But once I need it in an emergency basis, I can get it on the spot. This is better than borrowing or asking helps from friends and relatives. Do you agree with me?