I can’t imagine this being a great long-term deal for Google. There’s minimal good new content being created on Reddit. Searching for useful information mostly brings up old posts, while new posts are heavily spam generated or designed to support AI learning.
I imagine buying access to historic reddit content from creation to ~2020 would be valuable. While paying for ongoing access to new content is going to be far less valuable and turn into AI devolution as we get to where AI is learning from other AI and spiraling into progressively worse outputs.