Its meant as an exterior product to withstand the car washes, and UV rays etc.. While it will protect the interior, The look it may produce on the interior plastic may not be the best and this thing is very hard to get off if you dont like the look of it.
BUT, this product is a water based product and can be diluted further, so a diluted version may be suitable. But then again it'll vary from interior to interior as the plastic quality/color varies from car to car.