Primarily toy weight. The infant will have a problem with its maintenance and transfer. If the toy falls, it can even get a tumor. It is not suitable for cuddling or playing scenes. Does not teach creativity. It's crude and all it can do is make noise.
Secondly volume. Żabka makes funny sounds but is loud. The child may be scared. The manufacturer did not foresee this. It does not give the ability to turn down the toy.
Third and probably the most important: the toy cannot be turned off. Once it starts to "sing", it is not possible to mute it. This makes operation quite difficult when the toy starts accidentally, for example when pressed by a teddy bear or building blocks or during transport. Then it can effectively wake the sleeping child. To turn off the singing frog, you would have to unscrew it and remove the battery, which is not a simple task.
It is also hard to believe that a frog can teach a toddler to count or to pronounce the first letters of the alphabet. This feature is rather a "gadget", an add-on that is intended to encourage parents to buy.