I have a similarly non-cynical view of this and am considering to implement something similar for myself.

The reasons are simple:

1. I don't want to wake up one day 20 or so years from now and realize that I'm old and lonely.

2. It's possible to lose friends/acquaintances if you don't talk to them for some amount of time

3. I am generally happy when people I've had positive interactions with in the past contact me out of the blue

4. However I am bad at doing this myself

5. It is reasonable to assume that the above also applies to many other people, so why not take the initiative?

Of course you could use this system to spam and annoy people, do unsavory marketing stuff, etc. but that doesn't mean it's not a useful framework for staying in touch with people who would be happy that someone is staying in touch with them.