Acadian Mining Corporation ADAIF

RE: Acadian Mining to buy back up to 13.28 millio

[Pawper]

I always heard that share buybacks are a good thing but I don't understand them, especially in light of the following excerpt: "All shares purchased by the corporation will be on the open market through the facilities of TSX in accordance with the policies of the TSX and will be surrendered by the corporation to its transfer agent for cancellation. The prices that Acadian will pay for any of the common shares purchased will be the market price of the shares at the time of acquisition." How does that reduce the float if the bought-back shares will be put back on the open market? I can see that a smaller float would increase the NAV per share but I don't understand that other part. Thanks to those wiser than I who can simplify this for me...... P.