You absolutely can. Heap allocation for every component is already unneccesary, but loose pointers on top of that is a huge red flag.

This seems like someone who isn't up to date with the most elegant and fastest ways to write C++. Charging money on top of that is egregious, not to mention that there are lots of great GUI libraries already. FLTK, Juce, Qt to name a few.

Heap allocation is necessary in real-world scenarios because it allows a tree of potentially derived widget types to be manipulated easily. This is precisely how any robust GUI library is implemented.