Sorry for the late reply. I don’t mean to try and cache all of Twitch and neither would I want to. Mainly the ability to know what game / activity they were streaming in a shoutout command is a great conversation starter and can also give people a bigger reason to follow that person (e.g. “oh that person played Rocket League. I love Rocket League!”)
It’s pretty common for shoutout commands (e.g. with StreamElements or Nightbot) to say something like “Hey check out Streamer_X at twitch.tv/streamer_x ! They were last seen playing SomeGameXYZ” and with v5, it’s possible to do this and retrieve what game the person was streaming because it’s returned with the info, but with the New API, even if someone hosts / raids you and a few minutes later you try to shoutout the streamer’s channel to folks in chat, the game they were last playing is already gone because they’re no longer live. Or if there’s a regular in the stream and he/she had just streamed the previous day, can’t retrieve their game. I really think this is a scenario that should be possible in the New API as well.