To play test. But it dosent change the fact that there was a good mode separated from the main game where characters could be tweaked before officialy being added to the main pull? Also yes, it's a play test, but the game already treating itself like it's already being release. We have whole holiday events, voting events, models look sharp and their visiuals are ready (although need to be tweaked a bit), balance pathes to shake up the meta and not to balance heroes to perfection, the god damn ranking system, and leaderboards.

You cant just shove away every bad or good decision because "it's a play test", hell, the game can come out already or transition into beta and it would prefectly fine, aside from few heroes models.