Some vibrations are bad, for that, you just need to consult an occupational medicine, which recognizes that in some cases (and for some occupations) vibrations can be bad for your health. This is particularly the case in construction-related trades because tractors, cranes and other vehicles generate low-frequency vibrations that can cause back and lumbar pain over the long term (due to chronic, not occasional exposure) but also headaches or certain peripheral nervous disorders. Similarly, the vibrations of certain tools: jackhammers, pick hammers and other such devices very often lead to upper soft tissue disorders, carpal tunnel syndromes, etc…
We are therefore entitled to wonder whether the vibrations of a vibrating platform are beneficial or rather bad for our health. Unfortunately, there is not much literature on the subject because the craze for vibrating platforms is relatively recent. There are, however, studies that show some positive effects of vibrations on the body and on the lower limbs (studies that have been done on elderly people or people at risk). Please note that all manufacturers have contraindications depending on your state of health. It is therefore difficult to judge (without a scientific study) the benefit / risk ratio, but it would seem that these vibrations are more beneficial than dangerous.