While the empty to full ratio of containers is debatable the general concept is sound, in my opinion at least. Checking those containers isn't mandatory at all but if you want more food (which you probably want) you'll get that at a decent frequency and ocasionally you might be rewarded with something nice on top of it.
There is also some logic to it. You'll find more food in containers in kitchens and storage rooms and you'll find high value stuff in 'treasure hode' like locations.
