Do I have to learn the cases?

This comment popped up on YouTube.

Great videos. but I have a question. in lesson 1C you pronounced CAELUM /djelum/ or something like it. C like an CH. But in this one, you say it as K… why is that? and watching this lesson, i´ve got another question. why do we have to learn this nominatives and adjetives things?? are they gonna be useful latter on???

Here is my reply:

There are two pronunciations for Latin.
I learned the restored Classical Latin in school. In the Classical pronunciation, Caelum is pronounced with the K sound.
Later, I discovered the Ecclesiastical, or Italian pronunciation. Here Caelum is pronounced Chaelum.
I abandoned the restored Classical Latin for many reasons. I talk about all of them in my book, Via. You can find it here: https://dwanethomas.com/via/
As for all the cases, yes. It is worth the time you take to learn them. They are critical. Not only that, but, if you decide later to learn German, Greek, Russian, or many other languages, you will have to learn the same cases. If you have already learned them in Latin, you will have a head start in those other languages!
Have a great day!