Yeah, this is audio jewelry at its best. Whoever designed this thing has absolutely no clue how a turntable works. Arm bearing and platter bearing need a 100% rigid connection, otherwise the tiniest movement of the platter translates into movements of the pickup and hence into a signal which is not related to the music.
Sort of true but none of the likely movement will be high enough in frequency to be picked up and output by a seismic transducer, which is what a pickup cartridge is.
At v low frequency the cartridge body moves along with the stylus, which is just as well otherwise the system wouldn't be able to track the record.
As frequency rises the cartridge body starts moving more than the stylus, so there could be output but it is spurious.
At resonance the cartridge body is potentially moving much more than the stylus so if excited by warps etc there can be a very big electrical signal but it is generated by the cartridge body oscillation, not groove modulation.
At resonance is the phase shift followed by the cartridge body starting to move less and less until around 2x the resonant frequency (depending on cantilever damping) the cartridge body becomes effectively stationary and its output entirely generated by stylus movement. From this frequency up the cartridge output will be a (fairly) accurate transduction of the groove.
The main requirement of the arm/platter "stiffness" is to maintain alignment not to make the output accurate, that is achieved by the basic physics of the way the transducer works.
In fact the more rigid the arm the higher frequency it couples plinth vibration to the cartridge body - which we do not want to vibrate since it is the "stator" of the transducer.
It still isn't simple because any vibration mode which doesn't have a node at the cartridge body will give output which isn't on the record but none of a record deck is "rigid" over the whole audio band - nowhere near in fact.
"Rigid" has been used in the marketing of record playing kit for so long it has stuck, but it is not as important as published, and I am sure there are plenty of well engineered record players that get a good balance of distributed stiffness and mass but plenty wrongly asserting the importance of stiffness alone, particularly at the "fashion" end of the business.
Having written all that this one won't be stiff enough to maintain basic cartridge geometry so is indeed, shite.