FWIW, I have suspended wood floors that are prone to vibrating with conducted energy. In my situation, it is somewhat extreme; even a light footstep can make it look like a minor earthquake is happening.
When it comes to making the choice to pursue isolation, the main thing is that you experiment a little. If you do detect excess rattling due to a transference of physical energy through the Speaker to the structure of the house, then yes, it is absolutely worth pursuing.
If you have hard wood floors, the Gaia may be the best option. I don't say that as a supporter of their product. There are other ways to tackle the problem that may cost a lot less, but that is another story.
For hardwood floors, the Gaia feet are supposed to be anti-marking. Most other solutions like the SVS Soundpath feet, while very effective, contain chemicals which will leave marks on wood.
Conversely, Spikes DO NOT isolate. Spikes COUPLE whatever is on them to the floor. Real Spikes are meant to be used on Carpeting and should penetrate the carpet to rest solidly on the floorboard. At this point it is all about stability, not isolation.
In order to isolate effectively on carpet, and get stability, you would want a damping platform which could couple to the floor with Spikes, then use isolation between the speaker and the platform.
Having lightly followed this thread, I know that this is beyond the actual scope of the problem you may have... IIRC, you are on wood floors. If the Gaia feet are successful at stopping your vibrations, cool.
If you want to pursue a new Plinth base for cosmetic purposes, cool too.
An experienced woodworker should be able to solve the problem. That said, I would recommend removing the Drivers from the Speaker before sending them out to a workshop, as this might become a larger project than you think! If you do choose to pursue and need to send the Speaker out, as you remove the Drivers, make certain to mark the leads to each driver so that installing them again can be done easily and with no risk of cross wiring the Drivers. (Of course, removing Drivers can be tricky, too, but can be done at very minimal risk as long as you are patient and know a few tricks.)
Good luck!