Fire proof wall safes seem like the best of many worlds. You can do all of the following: secure your handgun(s) and other valuables, conceal the safe in a readily accessible area, and protect your valuables from fire (a far more common calamity than theft).
The construction and locking mechanisms on these safes are VASTLY superior to most normal wall safes. However, deciding to purchase one is not so simple.
First, there are very few inexpensively priced fire proof wall safes. You can expect to pay between $300 and $600.
Second, installing them requires a very unique space. They are far deeper than normal wall safes and will not fit in your standard 4 inch deep wall space.
However, despite these drawbacks, if you have the right space for them they offer an excellent option for storing handguns and other valuables.
To install these safes, you will need extra thick walls or a dead space in the wall that can accommodate the extra depth (e.g., closet, bulkhead, etc.).
There are two main manufacturers of residential fire proof wall safes: Amsec (2 UL rated fire proof models) and Gardall (2 UL rated fire proof models).