For most people, and business travellers especially it is the best option - for the exact reasons capetonian mentioned.
It's faster, it's considerably more comfortable, work can be done easily and phone calls can be made en route and you arrive in the city centre, without security and the expense of extra travel.
Most people regard airports as an overpriced and stressful experience, because, well, they are. And ofcourse most airlines these days, especially ones priced 'competitively' are godawful.
You may love aviation, most people for good reason, do not.