When Paris was asked to choose a recipient for the Golden Apple of Discord, he accepted Aphrodite's bribe and gave it to her in exchange for Menelaus's wife Helen. Paris later took Helen from Menelaus by force (depending on the account she might have been willing, but her husband certainly wasn't). In theory, couldn't he have done that anyway? What role did Aphrodite play that made it any easier? I'm aware of several ways she assisted Paris and other Trojans during their famous war, but this was before (indeed, the cause of) that.
The earliest known account of the Judgement of Paris comes from the Cypria, a work which has since been lost. A preserved summary, however, states that:
Alexandros judges for Aphrodite, encouraged by a promise of Helen in marriage. On the advice of Aphrodite, he has ships built . . . When he gets to Lacedaemonia, Alexandros is entertained as a ξένος by the sons of Tyndaros, and afterwards by Menelaos at Sparta. Alexandros gives Helen gifts during the feast. Menelaos sails off to Crete, telling Helen to provide proper hospitality for their ξένοι while he is away. Aphrodite brings Helen and Alexandros together. After their intercourse, they load up a great many valuables and sail away by night.
There are no hints here that Paris (Alexandros) took Helen by force. Instead, we see that Aphrodite guided Paris to Helen, and apparently, to put it delicately, played "matchmaker" for the two. This is reinforced by, for example, passages in the Iliad, where we see Aphrodite explicitly trying to provoke Helen's desires for Paris:
Aphrodite spake: "Come hither; Alexander calleth thee to go to thy home. There is he in his chamber and on his inlaid couch, gleaming with beauty and fair raiment. Thou wouldest not deem that he had come thither from warring with a foe, but rather that he was going to the dance, or sat there as one that had but newly ceased from the dance." So spake she, and stirred Helen's heart in her breast; and when she marked the beauteous neck of the goddess, her lovely bosom, and her flashing eyes, then amazement seized her, and she spake, and addressed her, saying: "Strange goddess, why art thou minded to beguile me thus?"
So, yes, in theory Paris could have abducted Helen anyway. But he wouldn't have known to look for Helen in Menelaus's kingdom, nor was he guaranteed to be able to seduce Helen without divine help. At the very least, a willing Helen would have made things easier for Paris.
In this way, Aphrodite's bribe basically meant being a guide and "wing woman".