Is a prediction asset can be reusable ?
It's too expensive to create one for every NBA match for example !!

Unfortunately they aren't. This is a known problem.

> but now, we have threshold feed price, which remove the problem, and now we can borrow with margin call price < threshold feed price without worrying margin call.

The threshold price is not set for eternity. See e. g. this proposal: https://github.com/bitshares/bsips/issues/244
If this gets accepted the committee debt posiition would instantly be margin called. Also note that the external price for BTS is less than 0.19 CNY whereas when selling CNY on the DEX you have to pay 0.202 CNY/BTS. In other words, the committee would lose more than 6% with this deal, even without BTS going down.

Ok.Nobody is "blocking" the proposal. Actually I think it's much better than BSIP-76.

There is discussion going on because people want to understand it better. It was inaccurate in some respects, and it presented no explanation as to why the proposed changes would solve the problems nor why certain constants are set the way they are.

The problem is solved if Joe is allowed to pay his debt in an asset other than BitUSD.

No it isn't. How should it work?

1. Ana still has 500 bitUSD and relies on the settlement guarantee, i. e. she expects to be paid $500 worth of BTS whenever she wants to cash out.
2. The blockchain has created the bitUSD from thin air. It can only destroy them when they are paid back. If Joe pays his debt in BTC, then the blockchain can't burn the BTC, and even if it did the bitUSD would continue to exist.

I agree with your analysis that with many people sticking to their bitAssets instead of trading them the system can't work if the collateral is in a downtrend. However, BitAssets come with the promise of stable value. With that promise, it is only natural (and perfectly acceptable IMO) that people buy and hold BitAssets when BTS is in a downtrend.

What's missing is an appropriate incentive for BitAsset holders to sell their holdings, thus reducing the debt. The original design of BitAssets came with two such incentives, both of which have been effectively scrapped by now:

1. MSSR - a large MSSR rewards holders for selling into margin calls. Because this mechanism leads to a premium on the market price (and because it is expensive for debt holders), MSSR has been reduced further and further, which has improved the peg but also removed the incentive to sell into margin calls.

2. Global settlement aka Black Swan - global settlement is like a Damocles' sword pending above both BitAsset holders and debt holders. It sets a limit to the promise of stable value, and thus provides another incentive for BitAsset holders to sell their holdings, because if they stick to them for too long they will start losing value. Thanks to Global Settlement Protection, this threat has been muddied and partially removed.

according to the community's consensus.

There is no consensus wrt the price feed. A decision was made by a majority of stake.

I created 2 committee proposals to remove the "witness_fed_asset" flag from bitCNY and bitUSD.

https://cryptofresh.com/p/1.10.50330
https://cryptofresh.com/p/1.10.50333

Thanks @abit . I support this.

I like very much the idea from Dan Notenstein aka blocktrades to use BitShares Decentralized Exchange (DEX) market for BitUSD and BitCNY pricefeeds.

I have often pointed out that this will create a feedback loop, because the feed price already affects trading activity on the DEX. Feedback loops are inherently unstable and dangerous, and should be avoided.

I suppose you mean this:

{
          "amount": {
            "amount": "38611393904",
            "asset_id": "1.3.0"
          },
          "extensions": [],
          "fee": {
            "amount": 47737,
            "asset_id": "1.3.0"
          },
          "from": "1.2.90162",
          "memo": {
            "from": "BTS8BbZqGbPVjHkYtswX92QbJwgAKovnwkRddW4Qq3zvyLYWKCD88",
            "message": "aec3266640276c866e87de1a891441c6",
            "nonce": "401396210379214",
            "to": "BTS7N3Y2ozxLvnRk5z2bQXHoTY431aLnizi1KhjcU1CreYtXrZM8C"
          },
          "to": "1.2.444403"
        }

"BTS7N3Y2ozxLvnRk5z2bQXHoTY431aLnizi1KhjcU1CreYtXrZM8C" is the memo key of the recipient. The recipient *account* has ID "1.2.444403", the sending account has ID "1.2.90162".

It seems that the explorer is out of sync. Other explorers show the transaction, e. g. https://bitsharescan.com/account/joeboomofo, and it's also in your account history on https://wallet.bitshares.org/#/account/joeboomofo .

Then I don't understand your question. If you've done your own gateway you should be the one who knows how it works.
What does your gateway do if not the points I listed above?