Jshell and REPL required to use?

Craig,

I am following along quite nicely and not having really any issues, however, I had one small question or two.

Is it a requirement to learn Jshell and REPL to learn Java itself? From what I am gathering is that they are both just useful tools to use in cahoots with writing Java. Can you tell me the purpose of spending the time we are on being instructed to use Jshell and REPL, instead of on purely Java stuff?

Also, if someone is planning on using IDEs and such in the future once that person is all proficient in the language and the chosen IDE environment, will Jshell and REPL really have a big impact on what that person is doing later on?

I know some people will use them both, and some won't. I came to learn Java and sometimes I get the feeling that the time I have spent so far in REPL and Jshell has either taken away from time from learning the language itself, or has contributed a bit to a small amount of confusion that I have had to figure my way out of.

Not at all trying to bash either of them if ya'll are for some reason trying to promote them. Just curious what is the practical use of them, and what is the likelihood highly experienced java programmers use these day in/day out when they have the IDEs and such.

Thanks.