If I understood it correctly, they are adding it in the main app itself. Would a separate app make more sense, as YT is where I mostly go for watching mid/long length videos usually and their consumption pattern would be way different.

Also, would the recommendations work differently here, at present YT recommendations seem to have a very high recency bias. Short videos will have inherently different engagement metrics too, so hopefully recommendations for both work differently.

But this is why I was very surprised with the rumoured $50B value for Tiktok, there are plenty of players who can disrupt it. Companies like YT, FB already know how to build social video platforms at scale. Just need to nail the creation tools and recommendations.