It means he can do whatever he wants with the club no questions asked as he 100% owns it, something he couldn't do before.
- He can buy all the rest of the minority shares (they have to sell them to him if he wants them)
- There will be no general meeting as it's now privately owned
- Can load Arsenal with debt to finance other businesses
- Can get Arsenal to pay dividends and management fees as and when he wishes
Whichever way you look at it it's not good news.