In my opinion e ticketing is much useful as u can book ur tickets by just clicking!! U dont have to wait for hours in the lines for buying tickets!! I even support ur statement as sometimes it becomes a hell of a job as sites hangs and u fail to buy tickets but its not every time!!
The answer to the question is that 
1.e-ticketing is not effective in villages
2.a person who does not know how to use internet cannot depend on e-ticketing
3.everyone travelling using e-ticketing depends on computer and if there is virus in the computer it can be bad for them
4.this cannot be presented as a gift to  a person