Benefits of P2SH
1.making transaction smaller
2.wallet doesn’t need complex engineering to implement P2SH
3.shift the burden of constructing the script to the recipient
4.长的script不会存在UPXO里，存在INPUT
5.收钱的时候不会村长script，花的时候才会存
6.长script对应的fee，转移到了spending阶段
