Yes that would be my guess too, but then the documentation for this method says, "Is this enchantment allowed to be enchanted on books via Enchantment Table", so in my opinion it should be false.
I have created several Enchantments and succesfully registered them. They are visible in Creative Mode and can be applied to Armor. But now i want to disable that they are obtainable via Enchanting Table. When i do this like i think its done the enchantments are not visible in Creative Tab and cannot be applied with /enchant. I am not sure if i have fully understood those methods:
public boolean canApplyAtEnchantingTable(@NotNull ItemStack stack) {
return false;
}
public boolean isAllowedOnBooks() {
return false;
}
This is how i disabled all enchanting table use