If one needs to express oneself outside of idpo, one uses caespo. In english and esperanto you have to use at least 3 words to express a subject, a verb and an object. In a polisynthetic language they are often enclosed in one single word. Po provides two birds in one catch since idpo is polisynthetic and caespo is aglutinative. If everyone became a po speaker, everyone would be an esperantist.
Polisynthetic words are almost always more useful and economic.
With po one has a choice. Po is the most rapidthinking language in the world. One may read and write in po faster than in native languages. By computer, one may perform miracles with po. Imagine for example a born englishspeaking journalist who types all of his articles into his computer in po, presses a button and the computer instantly translates the text into english.