Some comments from @sipa in #12702.

___

Yes, I think `importmulti` is superior in every way, except:
* Slightly less convenient to use (it requires redundant information, as you have to explicitly state what you want to import, and then give the keys/... to enable that).
* ~Doesn't support P2SH-P2WPKH yet~. Added in #14454

The latter can be fixed by just adding support for that case. The former can be improved by adding 'default' cases (e.g. if you prove a WIF private key, it can permit omitting the address, ...).

{
    std::string label = value.get_str();
    if (label == "*")
        throw JSONRPCError(RPC_WALLET_INVALID_LABEL_NAME, "Invalid label name");
    return label;
}
static UniValue getnewaddress(const JSONRPCRequest& request)
{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    CWallet* const pwallet = wallet.get();
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() > 2)
        throw std::runtime_error(
            "getnewaddress ( \"label\" \"address_type\" )\n"
            "\nReturns a new Bitcoin address for receiving payments.\n"
            "If 'label' is specified, it is added to the address book \n"
            "so payments received with the address will be associated with 'label'.\n"
            "\nArguments:\n"
            "1. \"label\"          (string, optional) The label name for the address to be linked to. If not provided, the default label \"\" is used. It can also be set to the empty string \"\" to represent the default label. The label does not need to exist, it will be created if there is no label by the given name.\n"
            "2. \"address_type\"   (string, optional) The address type to use. Options are \"legacy\", \"p2sh-segwit\", and \"bech32\". Default is set by -addresstype.\n"
            "\nResult:\n"
            "\"address\"    (string) The new bitcoin address\n"
            "\nExamples:\n"
            + HelpExampleCli("getnewaddress", "")