I knew a guy whose laptop was stolen and it had a major companies game engine source on it - which was not open source (he had done some contract work for them).
Personally I used LUKS encryption on a system76 laptop for 7 years and it worked fine - still going in fact. I was always worried about it failing especially after an update, but that never happened.
For backups to offline media I still do use file-level encryption though.
That's why I understand businesses requiring full disk encryption on their devices and on contractor devices, because in their case they are fine with losing data as they have many copies of it elsewhere.