I agree. I think that a very simple, single function service like this could be useful. You know exactly what you are sharing and who you are sharing it with.
In the past, I've been known to take a screenshot of my open maps application (with my location shown on the map), and sms that to friends to let them know where I am if I didn't have the address handy. This is clearly a better solution.
Great point. The short-link makes it sort of like Bit.ly for location and easily shared in SMS, Tweets, etc. I also like the temporal aspect that you can control how long you will be sharing the link (ex: I pick someone up at the airport, so I share my location for a few hours to that person).
I tried to get my friends to sign up for Google Latitude but they didn't like the idea of it broadcasting a location when not needed.
So maybe an expiring short link is a better approach.
I like it.