Were you able to get your target score? I’m required to get at least a 505 for a medical school pathway program I was selected for. They told me that’ll be easy. I’m glad you liked the course and benefited from it!
505 is 64%-ile. If you normally test well above that, it should be easy, but the MCAT is unlike any test you have ever taken before, so it's impossible to say for sure. Almost half of all test takers cannot score above 500.
As you implied in your OP, courses will provide structure if you need it, and will improve your score if that is what's lacking. They don't magically allow you to get your target score. THAT depends on just what your target is, what your potential is, and how much effort you put in. That is different for everyone. Plenty of people score 520+ without a course, while many people also score below 500 with one. Your results really will be entirely up to you. Good luck.