I work on a system where id reuse was necessary due to memory constraints. We were identifying hundreds of thousands of objects using GUIDs and referencing the GUID of course cost the whole 128-bits. All this data also had to be networked.

We moved the system towards using arrays which are filled with object data and the index of the object in the array is now the id… the 32-bit ids were of course 4x smaller.

All this being said, we do not claim the objects to be “globally unique”.

Edit: if I could go back in time though, I still might give this pattern consideration https://lucassardois.medium.com/generational-indices-guide-8...