It Might look funny to those who are just watching it. But never funny for those who are using machines of such caliber and precision. These could kill the operator if it is not operated in a timely manner and especially when it has 8 gunners to use it, one must understand its complexity, every Gunner is given a count and every count alarms another gunner to get his finger bones on and off the trigger.
Marching helps them to work as a team and it induces unit cohesion. People who laugh must seriously try marching in public space, people will laugh at u because in a daily life no one walks like that. But a soldiers life is beyond imaginable. He has to be kept motivated every time and at every level. It is the basic tendency of Human Life forms to get addicted to something beyond their daily routines.
Every Army practices its own patterns to operate deadly weapons such as these. US Army too operates 155mm howitzers and they have a pattern of changing roles for each gunner after 10-15 rounds. And they follow a command and follow pattern rather the Indian pattern.