what are grappling dummys good for ?

well i ordered a grappling dummy and have been using it the past few weeks or so and what do i think of it well what grappling dummies are good for is practicing the motions of movements you want to do such as a triangle choke,rear naked choke and a cross collar choke but what they are not good for is practicing against resistance of course its a grappling dummy it isnt supposed to give resistance i found this out the tough way when i went to jiu jitsu class and sparred for a bit at the beginning and when i was at home i practiced two basic guard passes the first being putting the hands on the hips and using my elbows to open the guard the second being a standing guard pass and when i tried to apply them with my sparring partner i couldn't do it because with the grappling dummy it offers no resistance thus i didnt know if the technique worked under pressure or not. so in summary grappling dummies are good for practicing the motions of a technique but not for training against resistance