They slapped it in there because its common practice to use balance shafts on big displacement 4 bangers.
Its a comfort thing, like a quiet muffler, soft coushy seats, soft bad handling suspension, shitty quiet soft tires and quiet chocking air intakes.
Doesnt mean that changing your muffler, seats, suspension, tire and intake will damage your car, now will it ?
Besides, many people have removed the Balance Shafts on the QR25DE, and I mean MANY. And they all say that the difference in vibration is close to nil.
I guess the knock sensor is tooo sensitv.... BS was brougth in... but thats my opinion....
I guess the best thing to do is desensitiz the knock sensor(change location) and BS in the trash you should be ok