These have been used for a long time. It is required if you end up constructing a building where the plumbing (or at least some of it) is below where the sewer line in the street is. You've heard the saying 'S*** doesn't run uphill'. You need the pump to make this happen. By far, the preferable situation is to let gravity do it. Then, you can still flush a toilet when the power fails. But, people build houses where they can, and then have to live with the consequences. As you can imagine, since it is a nasty repair job, when the pump or tank needs to be serviced, it is not cheap. Because it is mechanical, it will break eventually. Be VERY careful about what you flush down the toilet, as man-made things can and will clog up the pump, requiring service.