When we use money, we sometimes forget that we use units of pounds or pence, euros and cents, etc.
In money that's not a real problem. As long as we're in the same country, people know what we mean.
e.g. "That comes to 9 99" is understood to mean "That comes to 9 pounds 99 pence".
In Physics, however, it is essential that we are clear what we are talking about, since there are so many different physical quantities.