Some comments from @sipa in #12702.

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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, ...).

"Alternatively, the user can specify totalFee, or use RPC settxfee to set a higher fee rate.\n"
            "At a minimum, the new fee rate must be high enough to pay an additional new relay fee (incrementalfee\n"
            "returned by getnetworkinfo) to enter the node's mempool.\n"
            "\nArguments:\n"
            "1. txid                  (string, required) The txid to be bumped\n"
            "2. options               (object, optional)\n"
            "   {\n"
            "     \"confTarget\"        (numeric, optional) Confirmation target (in blocks)\n"
            "     \"totalFee\"          (numeric, optional) Total fee (NOT feerate) to pay, in satoshis.\n"
            "                         In rare cases, the actual fee paid might be slightly higher than the specified\n"
            "                         totalFee if the tx change output has to be removed because it is too close to\n"
            "                         the dust threshold.\n"
            "     \"replaceable\"       (boolean, optional, default true) Whether the new transaction should still be\n"
            "                         marked bip-125 replaceable. If true, the sequence numbers in the transaction will\n"
            "                         be left unchanged from the original. If false, any input sequence numbers in the\n"
            "                         original transaction that were less than 0xfffffffe will be increased to 0xfffffffe\n"
            "                         so the new transaction will not be explicitly bip-125 replaceable (though it may\n"
            "                         still be replaceable in practice, for example if it has unconfirmed ancestors which\n"
            "                         are replaceable).\n"
            "     \"estimate_mode\"     (string, optional, default=UNSET) The fee estimate mode, must be one of:\n"
            "         \"UNSET\"\n"
            "         \"ECONOMICAL\"\n"
            "         \"CONSERVATIVE\"\n"
            "   }\n"
            "\nResult:\n"
            "{\n"
            "  \"txid\":    \"value\",   (string)  The id of the new transaction\n"
            "  \"origfee\":  n,         (numeric) Fee of the replaced transaction\n"
            "  \"fee\":      n,         (numeric) Fee of the new transaction\n"
            "  \"errors\":  [ str... ] (json array of strings) Errors encountered during processing (may be empty)\n"