Dude is talking about 40-50 square meters of tile.
Assuming it is only 10cm thick (not likely) that's 4-5 cubic meters of concrete, or about ten to twelve tons. It almost certainly has reinforcing mesh, which means just breaking it up is not going to be a party, much less toting it out and hauling it off.
Now site-work has to be done, the soil recompacted, graded, forms built, mesh laid and 4-5 cubic meters of fresh concrete delivered and like wheel-barrowed in, screeded, floated and troweled-off.
I agree absolutely that the results would likely be better, but that is a good bit of work for a guy working by himself that has no equipment or experience. Setting tile is not difficult or complicated, but everything is heavy, and it is hard work.