Syncups can be great for bringing a remote team closer together. But getting people to start them more often requires incentivising them.

Most people don't start syncups in the first place, because they don't believe someone will join.

By showing that a syncup not only "happened" but actually highlighting that there was multiple people on it you are changing the perceived "risk reward" profile of starting a syncup from "oh probably nobody will join and I'm the stupid person who started it" to "oh, other people synced up, this actually works".