It's a tool used to build other tools, some of which have non-trivial amounts of users.

It's also a tool used by e.g. journalists and government agencies that dabble in stuff like research and evidence, and it would probably be more cumbersome for everyone involved if Google instead had to process requests and provide copies of material for these purposes.

Otherwise they'd probably have made life much harder for the yt-dlp-developers already. Not that I think they're nice in any way, but I don't think they're seriously trying to fully eradicate yt-dlp or related software.