We invested in several of the 1000l black barrels (cheaper back then) when we first set up our water catchment system. We capture rainwater from all our tin roofs. The water in black barrels doesn't go green because they are covered, nor can mozzies hatch in them. We have a gravity feed pipe running to drinkers with ball cocks in in each paddock for the sheep. For the hens, we get their water direct from a black barrel, so we can scrub their drinkers every time we fill them. Our land is on a slight slope, so we have to pump water from the lower barrels, using an electric pump, up to one in our veg garden. This barrel is on a plinth to give a good enough pressure to use leaky pipe irrigation in the polytunnel. That worked beautifully for a few years but then the pipe became coated with soil and algae, so now we just use a hose from the barrel.
We would never use the collected water for drinking ourselves, or anywhere in the house, although I suppose it could be used to flush the toilets. It's fine for animals, fish, poultry and the garden though (we don't have any kind of filter) and we can keep our rather limited well water for the house.
Be aware, the whole system will freeze up in the winter. We have had 80l barrels freeze solid, and the giant black ones freeze enough that they take a week or so to thaw once the outside temp rises above freezing. So when it's cold, we revert to carrying buckets, often with warm water from the kitchen.