Maybe she actually intended to rob Bruce, but then changed her mind at the last minute.
"Wait... 'bling-bling in the New Year?' Ugh, did I actually say that? That's villain dialogue. That's cartoonishly evil, D-list villain dialogue! And here I am, robbing Bruce, the only one who... oh god no. I've got to stop this right now."
Or maybe she was dropping off her note but got momentarily distracted by the big haul in front of her.
"And now to leave this note for Bruce, to tell him that... ooh, money... No! Focus, Selina! ...To tell him that I won't be committing any more crimes this year."