okay, i know this sounds simplified but in an attempt to inject some clarity....
north america, the card on it's own seems to work wonders. entry to centurion in Mexico City plus all CO lounges. with just a ticket. in UK, BMI similarly allow access but for all others, you need to apply for the priority pass black card. it's still a comp though so no worries...!
it's been a valuable boon to me, for when my c class tix or other entry cards count, i almost always find the pamex lounges quieter.