How do you classify playgrounds according to the three Eligibility Criterias; Exploration, Exercise & Social?
As a parent of 3, I can see it as a great place for kids to exercise (and also parents if you join the kids or take the opportunity to exercise while the kids play) and to Socialise as both kids and adults often meet and talk to each other.
I pick socialize and exercise. If its a really cool looking playground, i might also pick explore because good play will probably engage the imagination.
I do not pick exercise, because they are not built for teens and adults to exercise. Niantic games aren’t intended for kindergarteners. (I also don’t select exercise at a dog park, because dogs don’t play Niantic games.)
I say “I don’t know” for Socialize. Parents socialize with other parents at some playgrounds, but not all. People without children should not socialize there, so IMO it’s not a GREAT place to socialize. It can be a great place to get yelled at, or police summoned, or just make parents and children feel uncomfortable - but I don’t think that’s great socialization.
Explore only if it has a structure that you might want to see for its artistic value. Like a giant wooden dinosaur kids can climb and slide down the tail.
But parents and teens play with the younger ones all the time. They make a great place for families to get some exercise.
Socialize and exercise.
Many people meet up at a playground to socialize with others, whether it be parents chatting while their kids are playing, or even the kids doing so. I met up with the other kids all the time at the playground, and I know of parents that enjoy bringing their kids to certain ones so they can meet up and chat.
And the kids get in some good exercise, and sometimes the parents get in on the fun, especially helping out the younger kids or spotting over certain parts, like monkey bars. I have for sure gotten a workout in watching kids at playgrounds!
At sake of going off topic, I absolutely exercise at a dog park. A lot of dog training and play is active exercise for the dog owner and dog. This may not be everyone’s experience, but it is most definitely the majority of what I see when I visit or even just pass by.
I don’t 
exploration all the time, but sometimes I think about how much active cultural growth happens at a playground for kids (and even their parents). I know part of that is culture of learning how to socialize with new people, culture of learning how to exercise, but it’s also exploring. And that’s a very active engagement in exploration for everyone.
Agree that dog parks are great to socialize at and get some exercise. Great places to do some dog training, plus throwing around a toy for your dog can be a bit of a workout.
You could also get exercise at a rock, bus stop, neighborhood sign. But they weren’t built for human exercise. Just because you CAN exercise there - would mean accepting everything.
I go to a dog park to facilitate my personal exercise routine. Thanks.
A lot of this stuff doesn’t seem right, to me.
I haven’t seen much in the criteria that suggests analysis is supposed to be correlated with specific game actions or activities. The points of interest all seem to be locations, objects, or venues that some subset of the human community can derive benefit from - in keeping with the core criteria and without violating any rejection criteria.
I see the questions as more like: would or could a sports enthusiast, a pet owner, a parent derive value from a visit here in a manner conducive to criteria? It absolutely doesn’t have to be something that fulfills my agenda at this time.
If Stephen Hawking had been a wayfarer, he would have recognized that a climbing wall, playground, dog park or church could satisfy criteria for some people. He wouldn’t reject everything that didn’t fulfill his own interests or capabilities, and neither should we.
Thank you all for a very thoroughly discussion. I fully agree with some opinions and maybe less with other - but have a full understanding and support for the reasoning. 
I know how I will categorise it forward 
Hi
Play areas are designed for a wide range of children. We have young children / young humans that drag parents along to events. So yes play areas are suitable for young humans who might play games to exercise.
As a parent they give you a good workout too. The midwife was always advocating the exercise value of pushing swings spinning roundabouts etc. and this applies to grandparents and great grandparents too.
The seating in a play area is not just for socialising but to recover from the workout, whatever age you are. 
I have been classifying them as social and exercise. Particularly novel ones also get exploration.
They’re exercise for someone, even if that someone isn’t me. Same with social.
Dog parks are a little more tenuous. But I will admit that I’ve seen more adult humans exercising at dog parks than at “exercise stations” at parks so… I dunno.
Are they “great” places? Probably not, IMO. But… I like portals. And even those horrible “exercise stations” make for a lovely ring of portals around a park.