In practice, things either don't exist, or are poorly implemented:
Plotting simple things take 30 seconds.
And that's if you don't count the time it takes to `] add Plots`, especially on Windows!
And the REPL is broken.
And the editor is slow and annoying (Juno or vscode).
And documentation ranges from poor (no examples, buggy between platforms, broken links due to version updates) to non-existent. For example, lots of tutorials will often link to broken links to official documentation, links that one time were thought to be working but now aren't.
And so on...