Well even if signature campaigns give us less earnings, it is still steady. And i agree that keeping a lot of bitcoins can't be considered as steady income because the price is fluctuating and we won't be getting enough here on a consistent basis.
Of course something related to investing in bitcoin is not included in a fixed income, while bitcoin prices are very fluctuating in the market, even you may not get a profit at any given time because bitcoin prices are very likely to go down in the market. So holding or investing in bitcoin is not steady income