Using a snapshot of the order book doesn't give a good sense of the cost to manipulate a market. For instance, Kalshi has a market about mars colonization by 2050 (https://kalshi.com/markets/kxcolonizemars/colonize-mars/kxcolonizemars-50). It would only cost $500 to push the probability up to 85% for a moment. It would probably cost millions to hold it there for more than a few hours.
I think the reason people cite Manifold is because it has a track record of being competitive and accurate. You wouldn't assume that an online chess tournament will be easy to win just because they are only playing for fun.
Using a snapshot of the order book doesn't give a good sense of the cost to manipulate a market. For instance, Kalshi has a market about mars colonization by 2050 (https://kalshi.com/markets/kxcolonizemars/colonize-mars/kxcolonizemars-50). It would only cost $500 to push the probability up to 85% for a moment. It would probably cost millions to hold it there for more than a few hours.
I think the reason people cite Manifold is because it has a track record of being competitive and accurate. You wouldn't assume that an online chess tournament will be easy to win just because they are only playing for fun.