Teams often struggle when they have members who haven't achieved a minimal level of competence with the simulation. If you are unfamiliar with the software, you will find that your experience in your team will be frustrating or worse; so, in the long term, it pays off to practice with Solo Mike.
Remember, group grades are allocated/distributed based on the evaluation of your performance by the other members of your team. If you are unable to fully contribute because of weak preparation, they may factor that into their assessment of your performance.
That is why you must achieve a minimum level of competence in the simulation.