This is really kind of a loaded gun question. While they do not create softer water they do help prevent scaling in your pipes and heat exchanges. The reason that water magnets for water softeners do not soften the water anymore then what a water softener would is really simple. They do not pull any of the minerals out of the water. Instead they create a magnetic field that your water passes though. The magnetic field temporarily changes the water properties. This effect will last for about 48 hours. So what does a magnet for a water softerner change? Simply put is while the water is in this state it promotes the formation of aragonite rather than calcite. Calcite is what creates most of the scaling in your pipes.
One of the things we would not recommend is adding magnets for water softners to a countertop bottleless water dispenser. Mainly for the reason of the pex tubing that most of these types of systems use. They are not prone to getting scale build up.
If you are looking to try a magnet for your water softener then we have a good variety of options for you to choose from. However, we are also not going to be the ones to tell you this is something you must have for your water softeners. There are all different styles of magnets for water softners from the style of earth magnets to electro magnets. I really do not think that there is a difference in the two.