Interesting moments are not synced to SFDC - they are displayed in Sales Insight, which is a plug-in for Salesforce. However, the data still comes from the Marketo system.
You can certainly create interesting moments based on the Opened Email Trigger.
Keep in mind that we can't always see that an email was opened. If someone uses a text based email or mobile device (e.g. Blackberry), which does not load any images, then we cannot see that the email was opened.