If your speakers have four binding posts, bi-wiring is an option rather than an upgrade you owe them. It can reduce interaction in the cable, but it does not double amplifier power or replace the speakers' crossovers.
What the second cable run actually does
A bi-wireable speaker separates the low-frequency and high-frequency sections of its passive crossover at two pairs of binding posts. With one cable, the supplied metal links or jumper leads join those sections. Remove the links and two runs can connect the same amplifier channel to the two sections separately.
The usual arrangement is one pair of connectors at the amplifier and two pairs at each speaker. Both runs still carry the full-range amplifier output. The speaker's own crossover filters do the frequency splitting, exactly as they do with a single-wire connection.
This is not bi-amping. Bi-amping uses separate amplifier channels for the different sections. Nor is it active operation, which bypasses or replaces the passive crossover with an active filter before the power amplifiers. Connecting a second amplifier without understanding the speaker and amplifier topology is not a harmless experiment.
The electrical case, without the mythology
Two identical runs provide more total conductor area between the amplifier and speaker. They also keep the large bass-driver currents off the physical pair feeding the tweeter section. That can reduce voltage-drop interaction caused by the shared cable impedance.
The size of that change depends on cable length, conductor area, the crossover and the load. On a short run of suitably thick cable, the shared impedance is already small, so the difference may be negligible. Bi-wiring cannot make a difficult speaker easier for the amplifier in any simple sense, and it cannot double the amplifier's voltage or watts.
A fair comparison needs more than adding an expensive second cable and declaring it clearer. Keep the runs the same length, use the same total conductor quality where possible, and level-match the comparison. Otherwise you are judging two different cable looms, not bi-wiring alone.
When I would spend on it
First confirm that the speaker manual supports bi-wiring and that all four metal links have been removed. Leaving them in place is safe with conventional passive bi-wire wiring, but it parallels the two runs and defeats the arrangement you paid for. Mark the high and low pairs clearly before reconnecting them.
Bi-wiring makes most sense as a final adjustment in a resolving system with suitable speakers, a good amplifier and speaker placement already sorted. It makes less sense when the existing cable is too thin for the run, the supplied jumpers are poor, or the room is causing the problem you are trying to fix.
A good single-wire cable with proper jumpers remains a valid answer. If the choice is between an excellent single run and two compromised runs chosen only to fill four sockets, I would buy the single run.
Two practical builds in the catalogue
The Zonotone AVSP-1200Q Meister starts at $146 and has a Bi-Wire option. It is a four-core, 7.5mm cable using 0.94sq hybrid conductors, which provides a manageable route into a purpose-built four-connection cable.
At the other end, the Zonotone Granster SP-8800 starts at $849 and also lists a bi-wire option. It offers Oyaide and Zonotone connector choices, including spades, bananas and pins. Those figures are list starting prices; cable length, bi-wire termination and connector selection determine the finished price.
For either build, both amplifier channels need the same wiring scheme and each speaker needs its high and low pairs labelled. Do not assume an amplifier's A and B speaker buttons are a ready-made bi-wire output. Check whether those terminals are common and what the amplifier manual permits.
You can compare single-wire and bi-wire-capable models in our speaker cables range. Send the exact speaker and amplifier models through the custom order form and I will confirm the termination count before quoting.