The DIN rail breaker are safe when installed for their intended use.
But a residential AC power system is not their intended use.
There are many rules and code articles about residential power systems.
All you can do is use top shelf products from a wholesale electrical supply store.
Note that any residential system update might require GFCI or AFCI breakers.
For a sub panel used to feed branch circuits feeding an audio system I do not see an NEC code violation using Din rail breakers.
The breakers are Listed for their intended use. Breakers are sized correctly for the branch wiring and rating of connected outlet/s. Therein receptacle outlet/s.
Enclosure used to house the breakers is Listed.
A dead front is provided to protect the user from energized live parts.
The assembly and wiring of the electrical panel is done by a licensed electrician.
The problem with the Isoclean audio grade electrical panel system is it uses 32 amp breakers. That does not meet NEC code if the breakers are supplying power to two or more 15 amp receptacles or a 20 amp receptacle. The maximum circuit breaker that can be used is 20 amp, per NEC. It doesn't matter if the branch circuit wiring is #12 or #10 wire or even larger.