Where are you based? Do you realize that for US-based members and others, LATAM Pass points have a "hard" (no simple way to reset) expiration after just 2 years? They don't let you extend expiration by points "activity" like other airlines do.

And they typically take many weeks to respond to any request.

So unless you can deal with all that, I would not recommend signing up for LATAM Pass if you are based somewhere with that 2-year expiration, if you're not going to be flying LATAM pretty often.