I thought this was a really great idea and would love to see people with more experience than me provide important use cases where it won't work. Or - if it do

I thought this was a really great idea and would love to see people with more experience than me provide important use cases where it won't work. Or - if it does work everywhere - why it hasn't been adopted? It seems to me that including an ownership role in the data type, and having an explicit ownership transfer instruction, is a massive simplification.