Do we really need to put the square brackets?

Question

I just wanted to get the feedback on which one is better considering the random variable $X$ and some function $f$ applied to a random variable.

1. $\mathbb E_{X\sim\mathcal N(0,1)}[f(X)]$

2. $\mathbb E_{X\sim\mathcal N(0,1)}f(X)$

Personally I like the first style better, since it can be tedious to track the expected value in some hairy cases without the $[]$ brackets.

Please let me know which one is better and and if there is any difference comparing the first and the second case. I think there is no difference, but I am not sure.