C++ works, but compared to other languages it's often no longer the most productive choice for UI work.
Modern UI code is mostly glue and state management, where fast iteration matters more than squeezing out maximum performance. And when performance does matter, there are also newer, safer languages.
For teams comfortable with C++ or with existing C++ libraries to integrate, it can of course still be a strong choice, just not the preferred one for most current teams.
For teams comfortable with C++ or with existing C++ libraries to integrate, it can of course still be a strong choice, just not the preferred one for most current teams.