These questions are all inter-related.  Technology can be loosely defined as utilizing tools, machines, or engineered systems to improve the human condition.  In that sense, technology started pretty much with the dawn of humans.  Learning to make crude tools from bone, wood, and stone and harnessing the power of fire were all technological advances for early humans.

In my mind, technology can be divided into two different categories: necessity and convenience.  Certain technologies started as comforts but became necessities.  Mechanical refrigeration comes to mind here.  A refrigerator may have originally seemed more convenient when it was first introduced, but now it is viewed as a necessity to keep food fresh for an ever expanding population.  The situation is similar with modern agricultural techniques and fertilization.  What at first made the job easier is now necessary to produce enough food for several billion people.

Technology helps us in our lives in ways both obvious and unseen.  The conveniences are the most obvious.  TV's, smartphones, computers, and the internet all make life a lot more pleasurable.  But some of the most important technologies are even more important but not as readily obvious to us.  Improved methods for oil extraction to keep up with demand, the previously mentioned food and agriculture technologies, and methods for cleaning wastewater and drinking water are things that we don't often think about but our very lives very much depend on it.

Technology is so important right now because we seem to have passed a tipping point where now the technology is no longer a great convenience but a necessity for maintaining the modern way of life.  Many people's jobs and livelihoods depend on modern technology and would be very different without it.  Enotes itself is a testament to the importance of technology in our own lives!