"The mouse is a surprisingly good value; the keyboard is just along for the ride."
The 7200 DPI mouse is mostly marketing; what matters are the 1000Hz polling rate and 400 IPS tracking speed, which mean it can reliably track fast movements in games without spinning out.
This is for a first PC build on a minimal budget, or as a secondary/travel set. The mouse is the main draw, delivering competent entry-level gaming performance for a rock-bottom price.
Anyone accustomed to mechanical keyboards will find this one unsatisfying. If your budget allows for separate purchases, a better keyboard is easily found for an additional $20-$30. This is not a long-term peripheral investment.