Hi @jmacman ,
Thanks for your post in the Community and hope to provide some insight on this topic!
To begin, may I ask what might be the best use case you have for an “Opened Email” metric trigger? Consider the scenario where you have this as a metric trigger but customers go back and reclick their old emails. Then it would send the same email to customers and customers might feel like this is too spammy for them, and unsubscribe/ not like your business. Klaviyo specifically excludes these metrics from being able to be used a flow trigger to be as less spammy as possible.
The reason you can still see these as options when creating a flow is because Klaviyo doesn't have any extra limitation in place when other ecommerce integrations share click or open data. Keep in mind, that as a best practice those integrations shouldn't be used as data for events to trigger off of as businesses should technically be already transitioned to Klaviyo at that point and using MailChimp in tandem with Klaviyo wouldn't go well with deliverability.
That being said, you technically can create such a flow by using a segment triggered flow with the rules someone opening or clicking an email. The difference here is that segment triggered flows only allow customers to go through once. Unlike a metric triggered flow to allow customers to go through multiple times.
Hope this helped!
Alex