The main effect of the treaty is that personnel mine production and trade has dramatically decreased, thus making it harder for (small) non-signatories to deplo

The main effect of the treaty is that personnel mine production and trade has dramatically decreased, thus making it harder for (small) non-signatories to deploy too. International treaties tend to be always somewhat aspirational and are often violated and sparsely enforced. This does not mean they don't have any effect.