Recently, there have been too many pump-and-dump schemes in altcoins. Looking at ZKJ, just a few lines down left me dumbfounded, reminding me of the largest loss I had with SATS, where a few lines down led to a significant loss. With a full margin model, I didn't even have enough margin to cover the losses, resulting in a huge deficit. Now, with altcoins operating unilaterally, I have switched to a per-position model. Even if the price drops, I would only lose the margin. In a market lacking liquidity, one must be cautious. Under a full margin model, if an altcoin drops suddenly, I wouldn't even have time to close my position, and I could lose all my margin.