Smartphones are not the wave of the future. They are the wave of now. Whether you are defined as a Millenial or someone older but with a substantial income the smartphone is a part of the existence of the majority in major demographic groups.
A recent survey from Nielson did more to state the obvious, especially for marketers, that the devices are being purchased and used in great numbers. If you are hesitating on your mobile strategy you could be leaving money on the table.
The demographics should tell the story for any company. Look at your target market. If they are likely to be carrying a smartphone then your marketing efforts better make the effort to reach them. It really is that simple.