It’s the recognition, not solely the value, which it is being conveyed. $2.50 is still worth more than $0.00.

Does that distinction matters to the person who the $2.00 and $0.50 is handed to? That’s an exercise left up to the reader to try.

Addendum: I interpreted the OPs comment to be regarding appreciation of people who work in roles not typically tipped in the course of their service.