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::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() < 1 || request.params.size() > 2)
        throw std::runtime_error(
            "gettransaction \"txid\" ( include_watchonly )\n"
            "\nGet detailed information about in-wallet transaction <txid>\n"
            "\nArguments:\n"
            "1. \"txid\"                  (string, required) The transaction id\n"
            "2. \"include_watchonly\"     (bool, optional, default=false) Whether to include watch-only addresses in balance calculation and details[]\n"
            "\nResult:\n"
            "{\n"
            "  \"amount\" : x.xxx,        (numeric) The transaction amount in " + CURRENCY_UNIT + "\n"
            "  \"fee\": x.xxx,            (numeric) The amount of the fee in " + CURRENCY_UNIT + ". This is negative and only available for the \n"
            "                              'send' category of transactions.\n"
            "  \"confirmations\" : n,     (numeric) The number of confirmations\n"
            "  \"blockhash\" : \"hash\",  (string) The block hash\n"
            "  \"blockindex\" : xx,       (numeric) The index of the transaction in the block that includes it\n"
            "  \"blocktime\" : ttt,       (numeric) The time in seconds since epoch (1 Jan 1970 GMT)\n"
            "  \"txid\" : \"transactionid\",   (string) The transaction id.\n"
            "  \"time\" : ttt,            (numeric) The transaction time in seconds since epoch (1 Jan 1970 GMT)\n"
            "  \"timereceived\" : ttt,    (numeric) The time received in seconds since epoch (1 Jan 1970 GMT)\n"