Yeah exactly they got trendy around the same time as CrossFit started up mid 2000s is not exactly old school and regardless see actually question miracle machine or gimmicky large piece of junk?
Ive never seen Crossfitters use them (though they may, I dont pay them much attention). Simmons invented it, Westside made it popular (Powerlifting). It helps for some back injuries, not all, so its not for everyone...
Some hate it... Its odd, It helped me gain 45 lbs on my DL PR in like a year, focusing on the concentric.
But I also over-did the eccentric (too heavy, to much stretch) and injured myself. (Im too tight from sitting for work for 40 years)...
Need to stay lighter, focus on teh range at all times (for me)..