As much as running the product permanently, would be financially...

As much as running the product permanently, would be financially beneficial in the short term, but it would kill the product withing 6 months.

The seasonal approach works well (especially in the smaller markets), as it will generate almost as much revenue and extend the life for several years.

You only need one wand
The eye cream is closer to being a bottom seller than a top seller, therefore the uptake of the wand would not be huge.
It will not drag new customers to the brand regardless as to how special the tech is.
It is a great way to change the behavior of uses to get them comfortable using a device, thus readying them for the next wave.

I am also very happy to see it still for sale in the two largest markets being Japan and China as they will be the largest volume consumers.