Strikes are for copyright infringement i think. Not 100%.
You can get community guidelines strikes (from YouTube), and copyright strikes (from whoever owns the copyright, not YouTube)
Copyright strikes are different from Content ID claims, which just means the copyright owner makes any money from that video, or they block it in certain locations, but as they haven't requested the removal of the copyrighted content it doesn't affect your account (That's why copyrighted music is still often used on youtube)
3 copyright strikes lead to the termination of your account
However, Matt would have infringed YouTube community guidelines, which include
"Spam and Deceptive Practices", which I assume YouTube found the livestreams to be under:
- Misleading metadata or thumbnails: Using the title, thumbnails or description to trick users into believing that the content is something it is not.
However similarly to copyright strikes, you still need 3 within a 90 day period in order for your channel to be terminated
One strike may lead to the loss of accessing "advanced features" which includes monetisation, however, they should be restored within a week.
A second strike within the same 90 days leads to the loss of multiple YouTube features for 2 weeks.