I think they are a great tool with two main effects. First, they limit min max players who like to "dip" into classes for abilities. Second, they add flavor to races and serve as additional abilities for two races (the half-elf losing the most from the loss of multi-classing penalties).*
I think if these aren't issues in your game they can easily be discarded. I think the half-elf needs something to replace their "favored class: any" advantage. The human, IMO, is still attractive without it (the bonus feat at first level is possibly the best racial ability in the game).
* Remember that the flavor added means races tend to dip into the class, not focus on it. A race with favored class Sorcerer is a race where most of the members have some innate magical ability, not a race that necessarily has a lot of powerful Sorcerers.