Speicifcally USD is a:
* scene descriptor
* geometry caching format
* GL Scene Graph viewer
though each of those can exist independently of each other, and it does support Alembic as a geometry backend.
I believe they didn't support alembic because the geometry heritage of USD predates Alembic being a standard, and they added features like overrides etc.
Though interestingly, Blizzard just added support for Alembic layers that would describe overrides as well, so it's definitely an odd situation between the two.
I believe USD with an Alembic backend will be the eventual outcome
though each of those can exist independently of each other, and it does support Alembic as a geometry backend.
I believe they didn't support alembic because the geometry heritage of USD predates Alembic being a standard, and they added features like overrides etc.
Though interestingly, Blizzard just added support for Alembic layers that would describe overrides as well, so it's definitely an odd situation between the two.
I believe USD with an Alembic backend will be the eventual outcome