Few questions on ERC4337.payPrefund

[livingrockrises]

I'm going over this code https://github.com/Vectorized/solady/blob/main/src/accounts/ERC4337.sol#L172
trying to understand / have below questions

1. Why does the result of call need to be explicity pop-ed ?
2. Why use codesize() specifically for argsOffset and returnOffset ?

@Vectorized

[Vectorized]

1. Compiler requires it.
2. 2 gas vs 2 to 3 gas.