I don't really get this. For starters how much content are we talking about? You only get 15GB on the free plan, stepping up to £8 a month for 2 TB which seems to be their biggest plan. External hard drives have been selling for about £20-£25 per TB, so only 6 months of Google storage fees. On top of that how long would it take to upload all the content you want to store? Seems like a pain.
As for the question of distributing pornography, it's likely that would still apply. You'd be disseminating that content outside of your home which is how such actions are usually interpreted.
On the whole, it sounds expensive and not really viable. Buy more local storage if you can.