I am assuming that the number of SCs is fixed. Therefore it is useful to have one that I might use when travelling. I will never need one close to home, but I might use it from time to time as Tesla is paying for the energy so I can save a few bucks. But it would be far more useful for me to have an SC in London, ON, which I could have used a couple of times in the last few years, rather than in Scarborough close to my home. The Scarborough site will be useful for travelers and condo/apartment dwellers.
For example, I used the Concord SC a week ago. I didn't really need to charge, but I had to spend 15-20 minutes making phone calls and answering emails and I was driving by so why not mooch some energy off of Tesla.