At first glance, PPP is indeed "DDR with hands," until you find out exactly
what you are supposed to do
in the game.
In Parapara Mode, you are to copy exactly what the person on the screen does. It is exactly the same every time, and has several repeated things to do for each
individual song, making it a sort of standard dance routine. This is much easier to memorize, since it's not like you have to remember every single arrow; just the dance itself. Once you memorize the song, which is entirely possible, you can set the arrows and on-screen dancer to invisible, and look completely cool doing the routine, AND getting all the arrows correct in the process.
In freestyle mode, the on-screen dancer is still doing the parapara routine, but is not mirrored to you (the camera spins and goes around her constantly). Instead, you are given completely unrelated arrows, so that you are supposed to make up your own routine. Mostly though, people just set it on hard
difficulty, and go into what we like to call "Crazy arm-waving mode." This gives PPP a bad name, and is NOT what the game is about.