There are many advantages to using the full Google Ads product, vs. Google Adwords Express (Google Smart Campaigns).
You can ensure Spot 1 / Page 1 placement, if you're willing to spend/bid high enough. You can also control various keyword match types.
Ad Extensions are available and recommended. These help extend your brand presence and increase the click through rate.
You can also optimize for conversions vs. clicks, which means that Google's algorithm is more likely to show your ad to people who convert on your site vs. just simply click through. This is done via Google Analytics integration.
I explain in this video, when I presented to Vanderbilt University's Masters of Marketing class.
Paul Hickey, Founder / CEO / Lead Strategist at Data Driven Design, LLC and founder of WooCommerceUniversity.com, The Voice Designer, and The Voice Event, has created and grown businesses via digital strategy and internet marketing for more than 15 years. His sweet spot is using analytics to design and build WordPress websites and grow the audience and revenue of businesses via SEO/Blogging, Google Adwords, Bing Ads, Facebook and Instagram Ads, Social Media Content Marketing, Email Marketing and most recently, Voice App Design and Development – Alexa Skills and Google Actions. The part that he’s most passionate about is quantifying next marketing actions based on real data.