Really, it's for anyone who's core competency isn't selling general-purpose compute, but will have to design their own ASICs anyway.

For example, when WD open-sourced their SweRV cores in 2019, they also committed to shipping 1 billion copies of the particular design. Beyond just the software ecosystem, they might be looking at incentivizing IP vendors to contribute to a rich ecosystem of interconnects, peripherals, and design/verification software.