The Nutribullet seems to me more of a smoothie maker rather than a juicer
And why do you add water?!?
It is really.
I bought the Aldi own make Nutribullet and find myself adding much more veg to things - eg I make my own soups, pasta/curry sauces etc using loads of different veg, I can even throw in things I don't like

I find it very convenient and it's definitely increased my fruit/veg intake. If I have fruit/veg on the turn, I jsut chuck them in the nutribullet and make use of them
It DOESN'T do juice though, it is more of a smoothie. My parents have a proper Nutribullet and that doesn't either, though it does chop things marginally better than my copy.
You add water so you aren't consuming so much sugar... i.e. if you blended 8 strawberries, 2 apples, an orange, a banana and some cherries, you wouldn't have that much in terms of volume, but it contains more fruit than you would eat in a sitting and is much easier to drink... adding water dilutes it so it goes further. Similarly, you are meant to add predominantly vegetables, rather than fruit for the same reason.
If you want juice, get a juicer. Although I would recommend the Nutribullet for the reasons above, it isn't the same.