Except that maybe it's precisely because it was meant as an OO database that you can now enjoy jsonb or geography datatype that are pretty complex.
Also a lot of OO mechanisms become really useful without being clearly identified. For instance every table automatically generate an object definition (aka composite type aka rowtype) that you can use anywhere to ensure that a return type conforms to this definition. You can also check and validate single row well ahead of an insert attempts filter out and store unmatching data structure in an generic human readable rowtype while accepting correctly formated entries.
PS: I don't now if my examples were good or understandable but heck I tried, feel free to correct me if needed ;)
Also a lot of OO mechanisms become really useful without being clearly identified. For instance every table automatically generate an object definition (aka composite type aka rowtype) that you can use anywhere to ensure that a return type conforms to this definition. You can also check and validate single row well ahead of an insert attempts filter out and store unmatching data structure in an generic human readable rowtype while accepting correctly formated entries.
PS: I don't now if my examples were good or understandable but heck I tried, feel free to correct me if needed ;)