Called Samsung Pay support line because after factory resetting my phone, I can't download the app anymore. But I did obtain a lot of information though. The rep told me that the official release for the app is going to go live Sunday night and that everybody (GS6 and above) will have the app by Monday morning. Also, he said that they are in talk with a lot of banks and that new cards are going to be added on a weekly basis. So excited for this! Now I just have to survive going two days without using Samsung pay.
Update: Was able to install it again!