Sure, but if I want it to use Orbot, specifically, then it's on me that Orbot is available. This was the only way of knowing that Amethyst was actually using Tor. Now, I have no guarantees that Tor is being used. 

If you make a setting, and I say Orbot only, don't assume I want a bypass. Make that a separate, opt-in choice. It is not a given.