Yes and no. They provide entertainment to the surrounding area but they don't get visitors. This is on purpose as they would otherwise require road access and I use them a lot to fill in courtyards behind buildings and away from roads.

If you want them to get visitors, you can use Customize It to change the 3 values for tourists to 5. They will then need road access but they will also get visitors.

Are all of your paks and plazas functional?
In can people actually sit on them?