The big benefit of having an indoor Jacuzzi versus an outdoor Jacuzzi is that you will be able to use it more frequently. You can always use an indoor unit regardless of what the weather is doing outside. If it is extremely cold or rainy outside, it may not be a good idea to go outside to use a Jacuzzi.
Another benefit of using an indoor Jacuzzi is that it is safer. You are in the comfort of your own home and you do not have to worry about anything going on outside while you are relaxing.