Unfortunately, it isn’t quite that simple.
Google AdWords has standards that apply to search ads. When you create an ad group in your campaign both the ad and the keyword will be graded for quality and relevance and compared to other advertisers’ quality scores.
Your max CPC bid is multiplied by your quality score to arrive at an ad rank score. Your Ad Rank score must meet a minimum standard for your ad to display. This is done to prevent your ad from reducing the potential earnings for the search result page. It is better for Google to exclude ads that would reduce the overall revenue generated from the page, so they do.