I had massaging seats on my Citroen C4 Grand Picasso from 2014, and in the current SEAT Alhambra I’ve had since 2017. My opinion is that they are both OK but yes, a gimmick unless I’m doing over 200 miles without stopping & then they help a bit.
Would I pay extra for them? No Chance!
Get adjustable lumbar support instead, oh, and heated seats, I have heated seats on the Alhambra, they’re lovely in winter and last winter stopped a bout of spasticity from my spinal damage that would have meant I’d have had to have used my left foot accelerator pedal instead of the right.