As they say, "never ask the barber whether you need a haircut". I can predict that the merchant won't tell you if the product is snake oil, somehow.

From what I can see, it adds random props with random textures to your scene to "stimulate creativity". The odd thing I noticed is this paragraph: 

Quote - OR, 
after you've discovered
the secret to unlock your bonus extras
you'll have a total of:57 Shapes
x400 Textures
=22,200 Possible Props

Which sounds as if you have to go on a treasure hunt to unlock features in a program you've just paid for. The decision is yours, but I know what mine would be.