Regarding your question if it is worth it or not to go to Uruguay while in Buenos AIres, a great deal depends on the time of the year.

Buenos Aires and Montevideo are very close, and also one hour from Montevideo there is Punta del Este ,which is an outstanding resort.

It is all a question of priorities, depending what you wish to do or see.

The funny part is that I was born in Uruguay, ;-) but believe me I am not being partial, Argentineans love Punta del Este and flock there during the Summer time, ...

Graziella Miami Beach.