I see one significant upside: combined with a chat, you can ask the content creator questions directly

Interaction with viewers is the primary one.

There is also the "event" nature of streaming, where the audience is excited to react to things together in real-time, like when people Tweet when watching the Superbowl or a show's season finale. Even for mundane streams, the "chat" will happily talk amongst themselves reacting to whatever the streamer is doing, which can feel like hanging out with friends.

There's also times where the streamer is discussing something that is happening now or just happening (world events, the Superbowl, a game update, etc), where viewers are excited about the content right now and don't want to wait for the traditional record->edit->release cycle.

Ah thank you, this is the missing piece! That makes a lot of sense.

Live interaction with a community is pretty big.

Some viewers prefer livestreaming, and we see streamers catering to those audiences. It depends on the streamer, but often times there is much stronger sense of community when there is a live, topic-oriented chat, especially when the streamer engages with the chat. This is not something you can satisfactorily replicate with prerecorded streams.

Streaming is also much more low-cost to produce, editing can often represent an unwanted source of complexity and loss of creative control.

Think of the difference between watching a live sporting event or a concert vs watching a recording of the same event. The latter might satisfy you but there's something different about the former.

Live streaming is inherently mor einteractive and there's a shared experience simply because you can't speed up.

I guess you could see that live-streaming is experience-based. VODs are results-based. Not strictly the case but there's a trend.

FWIW my YouTube live streams that go on for hours sometimes attract a total of 10-50 viewers who click in for even a second.

No one EVER interacts.

My 15-second YouTube Shorts of my cat get around 400 views, sometimes as many as 10,000!

Go figure.

The very important thing in modern internet media: parasociality with the audience. Only by being live can you have a conversation with "chat", whether that's individual chatters or the hivemind of very large audience streams.

There is a special skill of streamers who can play an action game on one half of the screen and read enough of chat on the other half to make and respond to jokes, at the same time.

Another consideration: youtube and twitch apply different music licensing considerations to live, so almost anything that involves music MUST be live and unarchived.