A lot of rebranding is just busy work, stuff for people to do to feel like they've done something without actually doing anything. Sometimes it's a good idea -

A lot of rebranding is just busy work, stuff for people to do to feel like they've done something without actually doing anything. Sometimes it's a good idea - maybe their previous logo was gaudy, maybe it's not distinguishable at different sizes, maybe it's outdated (a lot of people feel like changing a logo because it's outdated is a bad idea, but I think it helps convey that whatever it represents is up to date - people see software with a strongly 1990s logo and wonder if it will still run, people see a tax agent agent with an out of date website and assume they're coasting). In this case it sounds like a bad change. The old logo is easily recognisable, it's simple, it's had a ton of press, most people would probably be able to say "that's OpenAI" from looking at it. A plain black O is too generic. There are a million companies with O logos.