Sliders can mean anything from a cowboy slider all the up to a 1.5" slide plate with toe weights and long trailers. (I’m long removed from reiners, so I dont know what they use anymore)
I’ve put cowboy or baby sliders on my cowboy horses during certain times of the year based what we were doing, conditions, and how hard the horse wants to stop. Might be showing whether it be cow horse or steer stopping too.
At the local level, most places dont have the best ground to ask for a nice stop showing the horse’s potential. I’m not asking for a huge reiner slide stop, it’s about protecting from hurting himself. If you stop him in bad ground enough, he’ll quit stopping whether it’s a slide stop or not whether it be outside working or in the show pen.