Another question is why the UGC-NET exams (for eligibility to professorship) which were conducted online at registered exam-centres have now switched back to OMR-style (hand-marking the correct answers to the multiple-choice questions), while still charging the students the same as they did for online exams.
OMR (hand-written) answer sheets might be easier to manipulate, whereas computer-based response get directly sent to the UGC without middle-person interference.

https://youtu.be/M60pdd3Bc7g?t=2  NEET Fraud Explained in 2 mins! Dhruv Rathee Shorts

https://www.youtube.com/watch?v=k-DJ5BWWXG8