Antique question: has anyone ever found a piece of old furniture that’s been signed ans dated?

I have an (almost) 100 year old table that has 3 signatures on it, in a very inconspicuous place you’d never find unless you lifted the top right off. One is very clear, large and apparent belonging to a man and is dated in my hometown, in 1929. In old public records there is someone by the same name who dealt with furniture in some capacity.

Another I cannot conclusively make out but it’s much smaller, fainter, and harder to read. And yet another appears to be that of my grandfather who I know owned it (that’s why I have it) prob almost 100 years ago now judging by the 1929 date.

Why did people discretely write on furniture in those days?