Reason we use electronic voting machines since the 90s in India:
(1) The problem of booth capturing. In a massive population, law and order is a unique challenge that most of the western countries do not face. Local goons used easily get hold of a lot of ballots and mass vote in 5 minutes and then run away before the law arrived. EVMs are made in such a way that every button press needs about 45 seconds to a minute after which you can vote again.
(2) The problem of illegal votes. Button based voting is precise. No chance of illegal votes.
(3) The problem of counting votes correctly from such a massive population. The chance of making mistakes is a lot higher and this is a unique problem that the west have never handled.
> The convenience of getting results a couple of hours earlier
Its actually a matter of many days here. The window for corruption is too high. And there are too many human vectors who can be compromised by bribes. EVMs just throw all of that out of the window.
(4) I will just mention environmental factors, although its not my main point. More population = more paper. We have 1 National Election, about 29 State Elections (28 states, 1 NCT), 1000s of municipal elections, and 10s of thousands Village headman elections!
This means some kind of elections all year round are always ongoing!