Hi Kouraib Abdmalek,
I shared that method because I ran into the same issue yesterday, and it sorted it for me.
It does work for baking splines, but the video misses a step. After you calculate the Point Cache, you still need to bake the cached spline using Functions > Bake Objects in the timeline panel.
That way, the spline points get baked as PLA keyframes, which is handy if you need proper keyframe animation (like using it with a Step Effector’s Time Offset).
I’ve attached a project so you can see what I mean.
Sorry, should’ve explained that bit better!