I think I can thank this maintenance Events end while i'm asleep and i thought i was safe. Made it barely:Splendid. 24 minutes before the event ends the server goes into maintenance mode. That means that nobody can make any progress while the clock ticks away.
I did not spend any diamonds and got in gold league. That's not normal.
It's not abnormal for this style of event on beta if you play it actively and wisely. There's enough ways to screw it up that most people won't fall in that category. (wasted keys, overspawning). Plus it's beta so a significant portion of the event population is there just to peek at its mechanics.
Live depends on your server - there are worlds in some regions where it's possible live too I think - but generally you should expect to have to spend some on live US worlds at least. Because there's a larger portion of spenders to compete with "just playing it well".
Incidentally I *did* spend some diamonds for my barely-gold. But my play was sporadic. Possibly missed some daily logins and free resets. Definitely missed free keys from daily challenge most days. And did both rivals in 1 day when ideally you spread them over 3 to keep your reset costs down.