This is because in general the wallet should still be easy to destroy in case of a 5$ wrenching attack 
Physical destruction of HWs in "most cases" isn't going to give you enough protection against such attacks [unfortunately]... A decoy wallet would probably provide better protection, but this feature doesn't exist in some of the HWs.That’s true for most wallets but it’s kind of a design flaw from the manufacturer, since it is an important security feature to be able to destroy the device easily. Not only because you need it in case of an attack but also if you want to throw away your device after it is old. In my coldcard the secure storage devices are clearly labelled and easy to destroy for example.
