I wouldn't do a mailing list these days, but as someone who spent the early part of my career interacting with devs that preferred this method, it's actually pretty ergonomic by a 2005 standard. A message thread aware, text based email client that can turn messages into patches in a keystroke makes it actually pretty comparable to modern code review...

I think it's hard for younger devs to get this because they're used to email being stuck in a crappy, unthreaded browser interface or Outlook etc. (which are terrible for mailing lists) and most collaboration taking place in code review and chat platforms like Teams/Slack but for decades before these were feasible, email was the way...