Hello

I was told that there is a tight connection between shsders and bone animation \ animation blending
In other word the use of shaders will superseed the traditional bone animation
is it true ?
If so, why ?

Yes, I think it's just a matter of multiplying the vertex position with a transformation matrix built from the bone(s) position/rotation. Since the GPU is much better at matrix multiplications than the CPU, this usually results in a performance increase (unless your application is GPU bound).

Thanks
It is the same explanation I was given
The point is, in my opinion, that Skeleton animation is normaly considered more suitable for animation blending than vertex animation
A rigged model is not a must for animation blending, you could use also the procedure described by you but normally it is not of use being more complex
Does shader provide any additional advantage ?