Certainly better than no house. But anyone who’s dug a hole and then watched what happens when it rains will know that the rain runs/seeps down into the hole. Likewise, by its very nature, any soil which can be successfully turned into mud (a.k.a. daub) is not going to be very rain resistant. Prehistoric people took to whitewashing their wattle-and-daub walls for this reason, and they made their roofs out of something else. I’m also guessing those ridge tiles are more decorative than functional. I say this as someone who lived in a house where a decently high wind once blew our heavy glazed terracotta ones into the front garden.
This. First thing I’d want is a platform to get above the insidious damp, then a roof, then walls.
Once the trees were all gone, Vikings in Iceland built houses much like mateyboy in the vid has - tho’ they had the sense to choose slight elevations to build on, then stacked turf and stones for walls and then thatched the roofs. Tiny, damp, but wind and earthquake proof; a handful still exist there since people were still living in them in a few remote farms up to the 1920s! Not the smartest people given they were surrounded by stone that naturally weathers into blocks, but they never used it - I think there’s only one stone-built building in Reykjavik - the old gaol; same with food, even facing starvation (Denmark did to them what we did to the Irish) it never occurred to them to eat coastal shellfish, preferring fish, same with waterfowl - they’d eat ptarmigan but avoided ducks and geese for superstitious reasons…
Daub walls = BIG roof overhangs, plus that clever mix of lime and animal blood - the proteins in the blood turn it into a surprisingly durable paint. Hence the tradition for pink walls in some places in the UK and elsewhere.
Yes. This can mean that surface run-off runs past your property and keeps going. A shallow ditch, open at the downhill ends, can take most of it around you. Something I would say for the guy in the vid is that he’s working in what looks like very sandy sub-soil. He could be relying on this being so well-drained that rainwater just disappears downwards. In the end the trick is to choose a construction technique which suits the surroundings/climate. Wattle and daub is great in hot dry parts of the world, as is unbaked mud brick.