She was definitely right in calling Luz out on her BS. Vee learned through experience just how good a life Luz had on earth. Vee succeeded at everything Luz failed at proving that Luz could have been just as successful herself since Vee was doing all this disguised as Luz.

Luz's weird antics prevented her from making any friends. It's Luz's own fault that she wasn't able to make any friends. It's no wonder why Vee was able to make human friends, unlike Luz.