When you get Claude Code's $20 plan, you get "around 45 messages every 5 hours". I don't really know what that means. Does that mean I get 45 total conversations? Do minor followups count against a message just as much as a long initial prompt? Likewise, I don't know how many messages I'll use in a 5 hour period. However, I do understand when I start bumping up against limits. If I'm using it and start getting limited, I understand that pretty quickly - in the same way that I might understand a processor being slower and having to wait for things.
With tokens, I might blow through a month's worth of tokens in an afternoon. On one hand, it makes more sense to be flexible for users. If I don't use tokens for the first 10 days, they aren't lost. If I don't use Claude for the first 10 days, I don't get 2,160 message credits banked up. Likewise, if I know I'm going on vacation later, I can't use my Claude messages in advance. But it's just a lot easier for humans to understand bumping up against rate limits over a more finite period of time and get an intuition for what they need to budget for.