If somehow you missed to get enrolled in regular engineering college and if you want to get engineering degree (equivalent) without attending the class (you may be doing job or other activities) then AMIE is best option for you in India.
If you pass sec A and sec B exam of AMIE, then you will get certificate which is equivalent to Bachelor of Engineering Degree.
By passing AMIE exam, you will be eligible to appear in UPSC civil services exam, GATE exam, many Engineering job at PSU. Many private company will also give job to AMIE pass out.
You will not need to dedicate full time for Engineering degree by getting enrolled with AMIE. You need to study yourself for degree course at your own place. You can read for it whenever you are free at your wish. Just give the exam, complete project and do practical, and you will get the engineering degree.
The fee for enrollment of AMIE exam is also very less in comparison to fee of private engineering college.
Any working people can get the engineering equivalent AMIE degree, and get promotion at his organization. People, who are interested in teaching career, can find AMIE much useful, as they will be eligible to appear in GATE exam and take admission for M.Tech from IIT/NIT.
People who missed getting degree in engineering must think of AMIE if he/she really interested in study.