perp futures,

[ghena]

I don't get it about PERP Futures
For example BTCPERP funding rate 0.12% (binance)

Reading for binance explanation binance won't take any fee. And if the funding rate is positive LONG pays to the SHORT funding rate. There is said it depends about markets, but as i see all funding rates are positive

So 0.12*3*365days=131,4% like more APY

I can easly go long spot long 1BTC and short 1BTCPERP and collecting funding rate with ridiculously high rate. Where is catch, i do not get it?

[logfiles]

Did you just say spot long? 
Never heard of anything like spot long. If you are talking about spot trading, then there's nothing like funding rate in there.

If you are talking about a long of x1 leverage, the funding keeps changing every few hours depending on an exchange. Sometimes it's positive and other times it's negative so believe me, at certain times you will be paying.