I understand how they work.......... here is a bit of a reprint from an older article, that the last part of it made me chuckle a bit.

...........................well, a lot. maybe they should retest.....
Because of the lack of internal damping, tonearm resonances have a more pronounced effect on the Decca than on other pickups, too. Slight torsional resonances that cause barely perceptible roughening of the sound of other pickups can put a marked edge on the sound of an intrinsically good sample of the Decca, as can pivot resonances and the undamped bass resonance between the cartridge compliance and the tonearm mass. Thus, while a fully damped arm like the Decca International will cause a perceptible improvement in the cleanness and sweetness of a typical pickup, it can make the difference between extraordinarily good sound or rather rough, glassy sound from a Mark V. So we will go on record as stating that, if you are not prepared to buy and install a Decca International arm, you
cannot get the best performance of which the Mark V is capable. If you'd rather not, you can get almost as good results from a new Shure/SME 3009 Type II Improved arm. (Oddly, the sound in
older SME arms is terrible—harsh, shattery and rough.)
A Rabco ST-4 sounds almost as good as the new SME arm with the Decca, but has earned a reputation as a system-buster because of its proclivity for scraping the stylus across the grooves as the arm lifts up at the end of a side. Paoli Hi-Fi 's Eugene Coggins estimates that more Mark Vs have been destroyed by use in the ST-4 than from any other single cause. The Mark V does not sound quite as good in a Rabco SL-8E as in an ST-4 (although it lasts a lot longer), but certain modifications (footnote 3) can make the SL-8E behave on a par with the Improved SME arm.
We also learned, much to our surprise, that many users have gotten excellent results from Mark Vs in, of all things, that dreadful little arm that comes with the Acoustic Research turntables. Will wonders never cease...?
Read more at
https://www.stereophile.com/content/decca-mark-v-phono-cartridge-page-2#XJDcYKMAzrfSmfXZ.99