It's the same as 4G vs 5G. They have a technical definition, but it's all about marketing.
It means 5 is more than 4, Claude only has a 4. Clearly 5 is better
Think about it. You walk into a video store, you see 8-Minute Abs sittin' there, there's 7-Minute Abs right beside it. Which one are you gonna pick, man?