Short answer: Maybe
Longer answer: Yes, some copywriting courses are worth it. But it depends on...
1- How much they cost in time and money
2 - How good the copywriting course is (material + instructor)
3 - What you're hoping to get out of it
1 - Everything we do to improve ourselves or our business comes with a price. We pay the price with our time, or our money (or both).
I would never invest much time, or even pay $50 for a copywriting course given by someone I never heard of, who's just regurgitating the same advice as 1000 other wannabe gurus.
But I would absolutely spend my time, and pay more than $500 for a course given by someone with a successful track record, and who offers one-to-one mentorship.
Which brings us to #2...
2 - How intensive is the training? And what's the reputation of the teacher?
Are the lessons in-depth, and can you contact the instructor (within reason) for follow up questions. I say "within reason" because nobody has the time, or should be expected to answer dozens of questions that were already clearly covered in the course material.
Also, does the instructor have real world experience selling through the written word? Or are they just repeating what they heard somewhere? (or preaching theory based on what sounds like it should work?) These things make a difference.
3 - What are you hoping to get out of it?
If you think you're going to take a basic copywriting course and instantly start making boatloads of cash, then save your money. Because you're going to be disappointed.
But, if you're taking the course to begin your journey, or to expand your current skillset, then that's the right mindset.
And now it becomes a matter of finding a copywriting course given by someone who's teaching style matches your learning style.
So that's my short answer, and my slightly longer answer to the question "are copywriting courses worth it".
If you'd like to hear my really long answer just let me know...