Yes, I blacklisted the kernel module for WiFi, but in principle some malware could sneak in and reactivate it.
I am not that paranoid, even with current prices my stash is not big enough to warrant the development of malware targeting my RPi specifically.
But I should probably blacklist the Bluetooth modules as well...
EDIT: Even the RPi 1 is not *frustratingly* slow. It maybe takes half a minute to start Armory, and a tx with many inputs may take 45 seconds to sign. Enough that you start wondering when it will finish, but still less than the time spend on swapping USB sticks etc.