It's not actually a 2 for 1. The bounce is disadvantage technically. Together though, they function better than your typical edict especially later in the game.
The flexibility aspect IMO is being glossed. Take a more powerful example.
Cryptic Command. How many times is that just a harder to cast
Dismiss? In our meta at least, most of the time (75% maybe more)? Show of hands.. how many run Dismiss? Another show of hands... how many people are thinking of cutting Cryptic Command for not being good enough?
It's all about the additional value of the other modes even if they aren't used as often. Having the option is what matters. Sometimes, tapping your opponents army wins you the game. Sometimes bouncing something is what you need. For all other times, there's dismiss for an extra U - not a good deal in a vacuum, but the whole is greater than the sum of the parts.
Far//Away is similar in that it gives you two different modes early and both later in the game. And unlike some other split cards, the two modes work exceptionally well together.
Cube is such a high powered environment, I find you do not have a lot of time to react to things. And that is where super flexible cards end up doing so much work. Even if on paper they look lackluster.