Although , there is one city in Uruguay: Montevideo. As for earning a living, if you can earn a living anywhere with internet, you'll be fine. Otherwise, unless you're very entrepreneurial, forget about earning a living in Uruguay.
I would only recommend that someone interested in the country spend some time exploring. Punta Carretas might appeal, but not to me: last place I would choose to live is in a city. Having spent time in both, I am blind to what people find appealing about Piriápolis and Colonia—for me, they're places to spend a half-day exploring and move on. We're all different.