They are absolutely essential and very practical. Most Indians have lunch which consists of different courses and carrying it all in a brown paper bag is inconvenient.
Tiffin boxes are easy to carry. keeps the food fresh as they are made of stainless steel. Some are even insulated so as to keep the meal warm for a longer period. It is very easy to buy them these days online and there is a wide range of variety choose from. Milton tiffin boxes are the most widely used. Check them out here