When someone says "common sense" or "no brainer" (etc.) what they actually mean it they don't want anyone thinking too hard about it and finding the defects/problem/lie.
Some landlords seem to think that the bond is theirs and use any excuse to claw it "back" from the tenancy tribunal (assuming they lodged it) at the end of a tenancy.
Other landlords seem to think that the bond is there to fund the depreciation of chattels due to normal wear, conveniently misunderstanding what depreciation is.
Bonds are already far too high. The limit, from memory, is four weeks' rent. Which would be OK if rents weren't over inflated (rent is approximately proportional to the equivalent of mortgage interest, though no rent drop when during record low interest rates!).
So, yeah, this is a thinly veiled exercise in transferring (future) KiwiSaver balances to (present) landlords.