Such a case is really able to save the ledger from being washed in a washing machine. In general, and not only from this. For example, from mechanical influences due to which the display may break or the printed circuit board break, as a result of which the device will fail. Case, after all, will not hurt, especially since the price of $ 20 is not so big. But on the other hand, $20 for a case for a $80-100 device looks a bit expensive. I think I would not refuse this, although fire protection is doubtful. It is unlikely that aluminum is able to withstand a large fire, but it can protect it from a small one. Ideally, such a case should be made of stainless steel for greater strength, but this will certainly lead to an increase in the cost of the case.
HW storage cases like this are very suitable, security is more guaranteed if HW is used and carried everywhere. The use of this case will indeed protect devices that cost $80-$100, but for some hardware wallet users it's not about the price of the wallet, but the content inside that is very important with assets that may be hundreds of times the price of the Hardware wallet. The materials used must be made of strong and rust-resistant materials for long-term use and any conditions, even these are also water and fire resistant.
~snip~
Sure, electronics may be salvageable, but there is no safer way than a seed phrase backup.
An electronic or hardware wallet can be purchased at any time, but the seed phrase will be very important and the only one that can be made. if you don't do a good and safe backup of the seed phrases, then it's useless. Hardware wallet vendors have provided boards or paper that are used specifically to record seed phrases.