What's good about those deals is that they're dynamic and responsive to what you have favorited in your roster. If you're the kind of player that was going to spend crystals on those items anyway, they're actually not a bad deal - of the ones I've looked at so far, at worst you're breaking even to straight crystal purchases - but often you're coming out ahead.
If you're not the kind of player that's going to spend crystals for that stuff - well they're every bit as good or bad of a deal as anything else you wouldn't be buying.