No, you didn't. You went for $90 PLUS the opportunity cost of earning all the points. If you did it with spend versus sign-up bonuses then the opportunity cost there is not trivial.

Points make a lot of sense if you're earning 25K+ each year. Anything below that and shopping on price and saving the extra you would have paid into a "travel fund" is going to offer a better RoI.

I hope that when you teach the class next week you offer full disclosure on both the costs and the benefits of this game, not just the upside.