yep, since the first day I started collecting Roger.
In some cases, you can literally buy a "sub-par" Tsuba which comes with a free box, for less than you can buy an empty box!! And I must admit, I have done this in the past.
Generally speaking about boxes, Japanese Kiri boxes are top quality, even the lesser ones are still above average. When you add in cushioning, there is a warranted reason for the (reasonable) cost.
I am a bit of a self-confessed box enthusiast; I collect, refurbish and sell carved wooden boxes/chests and I have seen so much differing quality and construction over the years.