Reasons:
- "YouTube Live" is the official name of the product (used both in the HC, and in media reports).
- "YouTube Streaming" has a bit of ambiguity as to whether the questioner is talking about streaming in the live sense, or about streaming in the netflix sense.
- youtube-streaming currently has 4 questions, all of which also contain the youtube tag. Given this volume, it may not be worth keeping, but then, I'm coming from a 10k questions per month environment, so my meter may be way off for this community.