In America, a decimal point is always written as a dot. In many other countries we use a comma. Therefore, many keyboards with non-english layouts have a comma-key on their numpad instead of a period-key/dot.
Having worked with various 3D engines and other design tools over the years, I have come to expect that the software I’m using is agnostic with regards to which decimal point I use. Both dot and comma work fine. UE is an unfortunate exception. A comma keypress while entering a value in an inspector window will simply be ignored, and users have to move their hand away from the numpad to type a dot, interrupting the workflow and years and years of muscle memory.
It seems like such a small thing but honestly it would make a huge difference in usability for a vast number of users outside the US (And UK I presume).
Thanks for reading!