Maxperson
Morkus from Orkus
Listed after arcane foci and they channel the divine obviously. And is it your contention that every kind of spell causes defilement on Athas, or just arcane?"Arcane" being in world fluff, and fluff isn't rules. What do druidic foci (listed right alongside arcane foci on the equipment list) channel?
Because bardic spells need music which arcane foci do not provide, or because bards do not know how to use one properly, or... Your multi-class example falls well short of being proof that the RAW on page 151 which says ARCANE spells is wrong.Which is why I mentioned multiclassed wizard/bards. As a wizard, a character explicitly learns to cast spells with an arcane focus. So they should be able to use a wand to cast a bard spell. But RAW, they cannot.
Because all spells can use components to override all else. If you want to avoid component use, bardic spells require their focus to provide music.Note that you do not need an instrument to cast bard spells. Whilst bards can use an instrument, they can instead use material components from a spell component pouch. Bard spells can be cast without music.
It does have weak mechanical meaning as the rule on page 151 clearly demonstrates. You're right, though, that it breaks nothing to allow any class to use any foci, or even to not require components or foci at all. Not breaking anything isn't proof that the weak mechanics aren't there, though.Now, if you wanted to rule that a wizard/bard can cast bard spells with their wand that would be a perfectly legitimate use of DM fiat. Because DM's call trumps rules. Alternatively, one might rule that a bard who is a devout follower of the god of music is casting divine magic. Since it has no mechanical meaning, it's not going to break anything.