the shareholder gets to decide what to do with the increase in proportionate ownership which occurs with share repurchases (at any price, "good" or "bad"). BBY Shareholders who sold into the repo to maintain their stake, realized the share repurchases as a dividend.
I wouldn't say buybacks are universally better (they are the same), but in a united states context, buybacks are almost always more more tax efficient.
For a $1 of pretax corporate income a dividend realizes
$0.2 of corporate tax (20%)
$0.08-$0.25+ of individual tax
For me personally $1 of pretax income distributed via divvy becomes about $0.56 of post tax income via the combo of corporate, state, federal taxes. If the corporation repurchases, the tax is deferred until when i want to create a dividend via sale of stock (which I may be able to offset with losses or push to a low income year etc). The share repurchase leaves the shareholder in control of choosing if/when to realize the individual tax and in the event one's basis is equal or > current price. the share sale may not trigger tax
For a retired couple w/o much W2 / ordinaryh income, there's a pretty generous exemption for qualified divvies, so that type is more ambivalent b/w the two forms of capital return. Likewise IRA money is completely indifferent.