The Pokemon Company and Niantic official announced that the Pokemon GO Plus device is failed. Not from the selling side but from the usage side.
Several features are not working as the Pokemon Company and Ninantic wants and at the moment they are working on to fix as much as they can.

The Pokemon GO Plus still available in all regions mostly from the Amazon but reviews and the feedbacks are not best. The Pokemon Company and Niantic released it to make the Pokemon GO easier to play. Using this device you can catch pokemons, grab the gift items from the stops or at least they wanted to do these and much more.

In the past more and more players left the game not just from the Android side (the game not working from September on rooted devices) but from iPhone side too. According to the players Niantic simple ruining the game with the useless updates and now the failer of the Pokemon GO Plus not helping in this situation.

Here you can find the official Twitter message about the failure of the PLUS: