It really depends on your child whether the investment is worthwhile.
Our HS offers quite a few courses along the same line. Students take a regular high school class and get regular grades, but at the end of the year they also get college grade and college credit. Most are through our local community college and there is not cost so the credits are automatic.
However, there are a few courses where we have to pay extra. There are some where you have to pay or you are not allowed in the course, and a few others where you can still take the course but if you don’t pay you won’t get the credit, just like you describe.
So the question is, can you foresee your child using the credits? For example, if it is a low level college math class and your child will be taking AP Calc senior year the math credit is useless. However it is possible that the history and lit courses will be useful as distribution requirements.
For S1 I was required to pay twice because he wanted to take the classes. He also had a ton of free credits. He goes to a school that does not accept credits of any kind so he could not use them.
For S2 I paid for 2 classes: One that he wanted to take, and another that I decided might be worth paying for. His college accepted the first class but as an elective so it is basically worthless. They didn’t accept the one I opted to pay for, but he did get credit for a few that were free.
That being said they both have numerous friends that received an entire year or more of credits at their colleges-it really depends on college selection.