Van Persie joined the Old Trafford outfit from rivals Arsenal for £24m last week.
Giggs is happy with the acquisition, and also praised Van Persie's desire to join the club.
"It [the Van Persie signing] sends out a big message. And it's great when a player comes out and says he wants to come to the club as well," said the 38-year-old.
"I'm biased but players should want to come to United because you're always guaranteed to be up there challenging for trophies, there's a great team spirit, top facilities and you get to play for a great manager.
"There are so many plus points."
United's next match comes against Fulham on Saturday.