As other have mentioned, it is the points that qualify you to be a blue card member.
I just sold a contract that was bought pre 2016 that was in a membership with a resale contract bought after that date.
That membership no longer has blue card status.
In terms of resort, all depends what you are looking for. I own at SSR as one my resorts. I bought It though to use at 7 months elsewhere during less busy times I like the resort itself. I am not a fan of buses to the park so I see that as a big drawback. However, when I stay there and do go to the park, I just pay to take a Lyft.
I love the laid back atmosphere and ease to Disney Springs. The other two are my least favorite. I have never stayed at OKW and whi,le AK is a gorgeous resort, it’s just not my cup of tea.