Copycats can copy confidently
Several chess coaches will warn you to not be a copycat (e.g. GM Seirawan in a video. GM Serper in a blog post) because this can act like a boomerang, against you.
But chess is beautiful : there's many exceptions on the many "rules of thumb".
On 1.b4 from white, I like to play 1...b5, since a while.
Especially in blitz that can make the white player, when it is new for them, think for a while (same for 1.g4 g5), and it also adds a little bit of psychological pressure.
Here's a peculiar game I just played where the symmetry was maintained for most of the game.