That's... a good point. I don't think I've seen a Youtuber that has superchats that did not have this feature. I'm fairly certain Phil did initially.
I assume it's something Phil had to manually disable at some point. I hadn't even noticed.
This give some insight into his desire for the SuperThanks - Phil is very interested in methods to hide money. Anything, even if it just means the numbers aren't visible to people on stream for longer than they could be.
It think it's also worth documenting the observation you mentioned in chat.
GameTrekker tipped $20.10 and commented about a playthrough from back in 2010. But GameTrekker has previously claimed that he is a new fan that just discovered Phil in the last 6 months.
This would appear to be yet another whale sock, and the operator either forgot the backstory they made up, or the name was stolen at some point since Trekker first started tipping.