old Substance account download points expire?

I have perpetual Painter license. I still have around 100 download points. I read that points doesn't migrate to adobe account if I have no active subscription. I don't want subscription for several reasons and probably will buy the steam version in future, but I would like to use all of my download points. Is there a time until I can use them without migrating to my adobe account? Are there any expiration-date on those Substance account points?
Also I don't understand why we not get any points for the perpetual license 😞