There is no evidence that convenient liquor sales leads to more drinking, and ample evidence to the contrary (in Quebec and the many US states that allow it). However, common sense is all that's needed to see the benefits: less driving. Beer and wine stores are so widely spread in our area that you practically have to own a car to get to them. In all of Waterloo - a town of over 100,000 people in a massive suburban sprawl - there are only three LCBOs and two beer stores.
Having wine and beer in convenience stores will also make corner stores more profitable, which should reverse the trend of declining numbers of corner stores. That will provide even more environmental benefits as residents won't have to rely on a car to pick up milk, the newspaper, and a host of other items.
In our older neighbourhoods you can still see where convenience stores used to be. They are usually on corners, and are often either boarded up or have been converted to a residence. They are reminders of a time when families either shared a car or did without, and were able to buy many necessities on foot.
We're always talking about creating a walkable city. This is how you do it: small, pragmatic steps that consider how people really live.