Nobody reads adverts. People read what interests them, and sometimes it's an advert. Digital marketing is not always overt, it's every blog, video and piece of content you see online, it's every link or mention on social media, it's every time you're compelled to enter your email address, it's every time you see that jacket you were tempted to buy, and it's every Google search page. If your business is not thinking about digital marketing, it's out of business.
Traditional marketing tends to interrupt. Take a billboard or printed advert for example, they interrupt a person reading a paper or going about their daily business, and as such, only hold attention for a short while.
Digital marketing however, is much more responsive, targeting specific audiences at specific times. The real opportunity that digital marketing presents, is providing value. If you can offer information and content relevant to that person's search, you can increase brand awareness, garner loyalty, trust and authority in your 'niche'.