The downfall would be the amount of time it takes the heat the water, even with the rapid heating system. This is a downfall that almost all of the inflatable tubs are going to have.  In 24 hours, the water will heat up to a maximum of 104 degrees. Some have reported that filling it with hot water to start off will raise the temperate in only six hours, but if you take this route, you’ll be spending more money on hot water.
They don’t usually use real water jets, but instead use fans to “blow” the air around (also because of the 120 volt outlet), which causes them to cool down much faster than a regular hot tub. This cooling effect is only made worse by the fact that the materials they are made from lose heat much faster than the materials used on a regular hot tub. All in all, you aren’t likely to get more than 15 minutes to a half an hour of good heat out of an inflatable hot tub.