The daily streak is a feature of the "?daily" command. If you use that command the first time, you will have a streak of one.
But if you do this the next day (in 24 hours) you will have a streak of two and will get 204 credits and not
202 credits. It's like a bonus for active users.
For everyone who has a userkey gets the double amount of credits. You can get a userkey by donating for LenoxBot.