Plenty Google Search users were appending “site:reddit.com” to their searches to avoid SEO and get actual human answers. This became less useful with the blackouts, and Google is actually addressing it - through a new feature called “Perspectives”. Allegedly the feature highlights forums and videos from social media (TikTok, YouTube, Reddit, Quora).
This means that those search users won’t beeline towards Reddit anymore. Instead there’s a reasonable chance that they end in Reddit’s competitors, including Youtube (owned by Alphabet, the same parent company as Google Search).
Given that 47% of the traffic of Reddit comes from organic search, this is going to hurt. A lot.
Reddit is in the process of closing down their platform. It is very likely that google won’t be able to just crawl their website in the same manner as they did in the past. One of the reasons for the current effort of shutting down the API on Reddits side is that they want to prevent folks from extracting their data. This is what all other social media sites are doing as well. So there is a very high chance that Google won’t have access to it anymore.
Buying it would guarantee them this access and at the same time prevent their competitors from gaining it. After all Reddit is likely one of the most valuable sources for text based human interaction for training these networks.
Google also doesn’t care about tracking Reddit users by their ID. That isn’t where the values comes from.