Used it for more years than I care to remember and have never yet rounded a wheel nut off,nor ever failed to remove replace one with it either!You must be using it wrong if you have!
Not me, I've never liked them and have tools better suited to the job. When you need a good heave on a 750mm breaker bar to undo a wheelnut a crossbrace isn't going to work. Many of them are poor quality and badly sized. Due to the design it's far too easy to angle it on the nut as you apply torque. This is even more likely if you add the locking nut.
I've been to far too many jobs where this type of brace has rounded both itself and the nut. Then you are into butchery and hope to get the nut off. Some are so bad that they ended up being recoveries.
Of course, the real problem here is incorrectly torqued wheelnuts, which is why I always use a torquewrench on mine.