I always know FLOSS are less forgiving to stupid user actions.
Also, effects of .ppt support could be tricky to implement, but please a warning or stop action window is far more better than program freeze: I tried several templates from which looks good, that I found libreoffice will hault on starting presentation.
I don’t know how program works, from my user experience perspective: don’t get whole program freeze.
Try some, ppts
The core issue here, is you must try to know if those work and instantly you got stuck without seeing any warnings.
May put a sign on loading .ppt,
“Warning: open these documents made from Microsoft Office may cause serious problem on your running libreoffice”.