Building the reset center is the only way to access Resetti and his brother Don and get their pictures. It opens up on a clear night if it rained the previous day/night and you can go down into it. It's not much but you'll get a few different interactions with both of the Resetti brothers and eventually they will give you their pictures after so many visits.
However, if you build the reset center that also means that Resetti will resume his job that he had in prior games of popping up to let you know if you reset the game without saving. He doesn't berate you for it nearly as much as he did in earlier games, but some people really don't like him so they don't build the reset center to avoid having this happen.
Personally, I like Mr. Resetti so I built the Reset Center and enjoyed visiting him whenever it was open.
Just causes Resetti to yell at you when you reset. Other than that, you can visit them and talk to them, there is also a chance you may get their pictures.