The boxes were sturdy and not too big so even if you packed them full anyone could lift them. The tops didn't quite fit and so would not stay on securely. We use these boxes to store papers and wanted to be able to keep out dust.
Like the design they're compact & can be easily stored until you need to use them. Then when you do they are simple to build. Also sturdy - can hold the weight of the files etc... even during back/forth travel & for re-use.