Biggest threat to democracy is moral panics about fake enemies instigated by politicians (specifically, demagogues). This helps with that by replacing politicians with direct democracy. It's more feasible than full-on direct democracy since it avoids the need for everyone to become an expert on every legal area. You can delegate your vote to a non-politician expert you know personally - and to different people depending on the proposal.
Ok. How will we not end up with echo chambers where there are one or two people collecting all the vote-rights for that particular chamber?
You might not. But at least you have the option not to do that.
Even if we agree that this is the biggest threat (in fact I think echo chambers are not a problem — as long as the ideas echoing around them match my preferences, haha!), I’m not sure why we’d evaluate these experiment by that metric. Maybe they are trying to solve some other problem.