@Elipsus
Ultimately, it doesn’t really matter. According to Suunto’s specifications, the Core 1 watch could be used at depths of up to 10 meters. You can even use the buttons underwater. This has been tested many times without damaging the watch.
Whereas, according to these specifications, the Core 2 can be used at depths of up to 2 meters only. So, it’s a hardware downgrade. This was confirmed in an email exchange with Suunto support.