It doesn't prevent the error, but it also won't take down your server when malicious users (or just lots of normal users) start to bang on that input with the problem, and your non-BEAM VM pool starts to run out of available preloaded stacks... You get a new Erlang process in well under a millisecond on modern hardware

It WILL log the error, with a stacktrace, so you have that going for you

Note that even with typing, you cannot avoid all runtime errors

Also note that this tech was first battle-tested on cellphone networks, which are stellar on the reliability front

Depends on the error. Lets say it is an error that happens once every 1 million users.