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, ...).

{
    bool fLabelFound = false;
    CKey key;
    pwallet->GetKey(keyid, key);
    for (const auto& dest : GetAllDestinationsForKey(key.GetPubKey())) {
        if (pwallet->mapAddressBook.count(dest)) {
            if (!strAddr.empty()) {
                strAddr += ",";
            }
            strAddr += EncodeDestination(dest);
            strLabel = EncodeDumpString(pwallet->mapAddressBook[dest].name);
            fLabelFound = true;
        }
    }
    if (!fLabelFound) {
        strAddr = EncodeDestination(GetDestinationForKey(key.GetPubKey(), pwallet->m_default_address_type));
    }
    return fLabelFound;
}
static const int64_t TIMESTAMP_MIN = 0;
static void RescanWallet(CWallet& wallet, const WalletRescanReserver& reserver, int64_t time_begin = TIMESTAMP_MIN, bool update = true)