I don't know why they did this, but in your profile there used to be a UI element that showed you when your next chest would be available so you would know when you have to play a new champ that doesn't have one yet. Sure, this might be ranting at highest level but it is yet another one of those "QoL" changes that add absolutely nothing to quality at all. I just hope they revert this because there is simply no point in doing that.
It should still be there. Let me check with our team. It’s there on my client, so it might be hidden because of a bug. If you can send in your .log file for the session to player support that would be helpful. Thanks for raising the issue!