My immediate thoughts are that it takes away a lot of the rhythm - like everyone else is saying, it's constant DM, and while a lot of people watching the stream were enjoying that, and I would agree that pushing should be incentivised over holding, having breaks in that action is important. In the few games I watched I didn't see a single spy play, for instance, because there just isn't time to set it up. I agree with #22 that the stalemate problem it's purporting to fix isn't really happening in 2022 at the top level, and maybe it's still common in lower divs but teams there just aren't as good as breaking them.
Having said all that, one event isn't enough to draw conclusions, and if teams practised this more they'd get better at playing it to its limits and maximising that 3min timer. It's possible that a good middle ground would be at 4 or 5 mins, as some people suggested, but I don't think we can say already that it's objectively good or bad, and tbh the best thing we can do is experiment with an open mind.