Depends what you’re doing with it, but for normal XC for somebody not big boned it’s strong enough – and probably as strong as bars which cost rather more. I’ve been using some KCNC flat bars happily for several years – thought I think mine only came at 600mm width (I’m an XC Jey boy so cut them down a bit!)
Normal XC only, and the tamer end of it at that, but I’m not light, hence a degree of worry!
I’ve always preferred bars at the wider end of the spectrum, never rode with anything narrower than 580mm even before risers came along. That said, I’ve not ever gone wider than 680mm, so I’m pretty mild these days…