Great for kids and dogs or for entertaining without someone to open and close doors for you as you shuttle things in and out from your backyard. It’s a solid barrier that parts when you apply pressure, but smoothly seals again once you’ve passed through.
Note: they also make this in an insulated version, where instead of keeping insects out, it helps to manage drafts, not only for exterior doors, but also to separate sections of the house or as a barrier to the basement/attic stairwell.
I’ve seen people use it as an actual door replacement in situations where they aren’t able to have a doggie door—they just install this and let the dogs go in as they please.