My reading of this is that the company has excess capital, and...

My reading of this is that the company has excess capital, and there are two main ways to give that back to shareholders - dividends, or capital returns (either as a direct capital return to all holders, or via buybacks on market). With dividends and capital returns, all shareholders benefit equally but don't have a choice as to participating in it or not. Buybacks allow the shareholder to determine whether or not they want the taxable event by selling on market, as an on market sale is an individual/company decision for the holder.

Some companies prefer to give shareholders the option to receive the capital via a buyback, as that doesn't enforce a tax event. This is especially true in Oz if there are no franking credits available. Other companies prefer dividends, and some like WES give cap returns also.

Each has benefits and negatives. I think NHC are simply saying for now, dividends is our choice.