अपनी संपूर्ण क्रांति, राजधानी से कम है के 🔥- Arjun Rai

From a technical standpoint, MEMUs and EMUs are exactly the same.As the name indicates, a MEMU is simply an EMU used for mainline traffic. I would not term the points you've mentioned as advantages, but rather, they are just the design requirements for MEMUs.
Both are designed for different purposes.
1) EMU coaches (12 feet wide) are wider than MEMU coaches (10 feet 8 inches wide) and EMUs are designed for handling more passenger traffic than MEMUs.
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EMU's have a larger passenger capacity than MEMUs. A 9-coach EMU rake is designed to handle 3900 passengers, while a 12 coach MEMU is designed to handle 3300 passengers.
3) MEMU's have better seating and features like stairs at doors, because they are designed to be used for relaxed schedules on main line routes. They are not intended to run at high frequency like suburban trains. MEMUs are just like passenger trains, but running with an EMU-style rake instead of a loco hauled rake. They are meant for passengers traveling relatively long distances, or 2-3 hour journeys. They are not designed for suburban crowds. For example, a MEMU running between HWH-KGP, will share the route with mainline trains, and have 2-3 minutes halts at stations.
EMUs (suburban) on the other hand, are designed to operate quickly. For example, suburban trains in Bombay or Calcutta have many services running just minutes apart. So, they cannot have long duration halts. So, in the 30 second-or-so halt, 100's of passengers have to deboard the train, and 100's of passengers have to get into the train. Having stairs and narrow entrances like MEMU's does not allow for such fast loading and unloading of passengers. So, EMUs have wide doors, and the platforms are constructed at a higher level to remove the need for stairs. So passengers can move in and out of the train much quickly. EMU's are not designed for luxury or comfort. Their only purpose is to move a large number of passengers in very short journeys, and have the flexibility to run a large number of trains in short intervals.