Making promises that might be implemented isn't "buying" a vote. As you said, that is an intended part of democracy. Promises are not guarantees. Instead, vote buying is giving an explicit quid pro quo such as paying $10 for every "correct" vote receipt.

Yes, this doesn't fix every problem, but it does fix some problems that used to be common.

> So your concern seems strange.

Then I strongly suggest reading more about the history of voting methods and technology. (the talk in my other post has a nice overview)

We no longer have problems like offering whisky for votes or employers that threaten to fire anybody that doesn't vote a certain way (although occasionally they still try).