Great question! When you set ePacket as the default, it only automatically selects it when it comes to processing and placing orders with suppliers. If you're just browsing imported products, it's still going to show you the other options first.
When you've got an order, go to Oberlo to place it, then you should see ePacket selected at the checkout. If you're still not seeing ePacket at the checkout of the order with the supplier, let us know!
I do however see how this can be misleading. I'll be sure to pass this on to our product team as I'm sure you're not the only one who thought that. Thank you for the feedback! Hope to hear confirmation from you.