Labour for me is human productive effort towards achieving set target.To answer the question, labour may be wealth, in the sense that when others labour while you fold your harms and watch from where will the wealth come from? Wealth creation cannot be separated from human effort both mental and physical.
Of course labor is considered an asset, labor is not only an asset but a valuable asset. The more industrious a nation is, the more developed it is. A lazy nation can never prosper on earth. Industrial revolution and agricultural development in a country requires an industrious nation. Japan, China and the United States of America are known as the most advanced and prosperous nations in the world because of their hard working people.
First of all, I would like to define if what is the word called 'asset'. An asset can be a crypto, gold, and real estate (only to name a few). It can also be something that can give us a reward or advantage. Labour can be one of it like you said because labour is usually a kind of job and when we have a job, we can earn a money. An industrious nation can also require more laborers. I think this is both positive and negative. So, those who are not industrious are not always negative and it doesn't always mean that they are lazy. Like it or not, there are still nations that are like that. They still exist on earth and they still can prosper on their own ways.