If most of us were thinking about posing as ground workers to find a long lost valueable treasure buried in the ground at an approximate location, we wouldn't think it was a good idea to advertise that on YouTube... but this isn't us, this is Tom Scott. Presumably this video is part of the deception/deniability plan, where in the future Tom can sit in a police interrogation cell and say "if I were going to dig into the foundations of a building to steal a precious coin, I wouldn't be stupid enough to announce it to the whole world on YouTube...would I?".