First of all the cactbot "solver" is not giving you a 100% success rate. It basically shows you which line/spot you should solve for in order to increase your chances. Something that is very easy to do even without the tool and you basically use the same method every round.
Secondly as far as I am aware you can't sell MGP rewards on the market board. So there is no real advantage to have. You're not impacting the economy in any way.