Had a group that would play DnD 3.5, where you need to roll to confirm crits (20 auto hits, roll again against AC to crit). We ended up rolling to confirm fumbles as well because catastrophic failure doesn’t just happen 5% of the time. Imagine 5% of your army accidentally chopping their foot off or beheading their nearest kinsman every few seconds.

I don’t use it myself, but I believe Proton (or Proton Mail?) doesn’t require any additional info. At least back when I checked it out before. There’s also mail.com, as well as a plethora of pros & cons lists for email providers out there to google (with add blockers).