Traditional websites scale down to the size of the screen it's shown in. This means that traditional websites reduce the text until is almost illegible, the buttons might be too small to finger tap them on a mobile screen and on top of it, Google won't position the content on mobile searches.
Of course there are responsive sites well constructed and other not so cool
A responsive website does adapt and move each part to display the content in an optimal way: font (normally) gets bigger and more readable, images are resized to fit the screen nicely and other functions are included such as finger swiping and other interesting features.
Of course there are responsive sites well constructed and other not so cool. It's important to take into consideration many details when buying a responsive site. If you have doubts or questions about this, don't hesitate to call us or send us an email.