On the one hand there is the possibility to insure the iPads, on the other hand a proper case makes sense in any case.

For example, Griffin Survivor offers very robust cases.
Please note that the iPad camera can still be used to scan barcodes.

For work processes that only ever take place at one station, it is also a good idea to put the iPad in a fixed holder. Here, the power supply should also be permanently installed.

The disadvantage here is that the camera cannot be used so flexibly and therefore the use of a hand-held scanner would be necessary.