The Julia crowd really need to hang less value on the REPL - people writing serious production code don't use one, and scientists using Python have moved on to notebooks. At this point, having Julia be so focused on the REPL is a weird affectation.
I used notebooks when I did my PhD using Python, but have moved to the REPL using Julia on my PostDoc. The Julia REPL experience is so much nicer than Python's, it removes the need for notebooks completely for me.
IMO, the REPL is really nice for exploration. I would never write code in it, but it serves as a really good doc search tool and quick way to check things. It helps that the Julia REPL is more inspired by the Lispy ones than python/R.