It explicitly says that 7% of their users are coming from UK. If UK blocks them, they will loose noticeable part of advertising revenue. If there was no money at stake, they could just ignore Ofcom and sleep well. But they appear to be very agitated about the fact that they may loose their second biggest market.
Honestly, I don’t understand anyone on 4chan side here: they are de facto in UK jurisdiction because they earn money from that user base, so either they comply or they leave. All of this freedom-of-speech and US lawsuit hype is just a distraction circus.
it's worse than china's firewall
So I would have to suggest, use these features with extreme caution on any page you consider private if you aren't prepared for your private information to get sucked into Google's Gemini training data.
If an actual ad played, I'd be irritated beyond belief. But when there's a 12 second buffer, I have enough patience training for slow load times that I instinctively just quickly check my email or spend a brief moment lost in thought. Especially when it's every video. If it was one in every 5 videos, I'd notice it and be bothered. When it's every video, it's part of the experience and my brain just cuts it out automatically.