As per the traditions of the infallible Imams (as), the day of Friday is reserved for the Imam of the Time, Imam Mahdi (as). Since Friday is largely considered as the day of zohoor (reappearance) of the Imam, this ziyarat assumes that much more importance.
While it is essential for Shiahs to convey salaam to Imam every day, this ziyarat is special because it is recited on the day reserved for the Imam (as). In this ziyarat, the believer salutes the Imam (as) through his forefathers and affectionately calls out to the Imam (as) saying that since this is Friday, the day on which your zohoor is ordained, come soon and extract revenge from the enemies of Allah and your enemies and please the hearts of the believers through that. Then the believer pleads to Imam (as) saying, O my master, on this day, I am your guest. You are an marvellous host, you are generous and the son of generous (Imams). So be an excellent host to me!
One of the benefits of reciting these loving sentences is that Inshallah, when the Imam (as) arrives, he will remember our dua and invite us to be his guest. It is the habit of worldly parents that they remember the requests of their children. Imam (as) loves us more than our parents and therefore he will remember our request well. Hence one should not forsake the recitation of this special ziyarat on Friday.