Yes, that is discussed in the book. He makes a big deal about the difference. In fact he discuses the seeming inconsistency of accountant putting large items into the "assets" column that do nothing but depreciate in value...

I'd argue that the main point of Rich dad, poor dad can be summarised as:

1) assets put money into your pocket, liabilities take money out of it 2) you gain wealth by adding to your assets instead of your liabilities

It's roughly equivalent to the dietary advice of "you lose weight by making sure there are more calories being spent than eaten"