Why are building systems connected to the Internet?

I have a question to start this post off. Why are building systems connected to the Internet, and what is their purpose? I’ve never heard of this until I heard it mentioned I believe near the end of Security Now’s recent podcasts. The article I found on this subject is called FBI warns industry that hackers could probe vulnerable connections in building systems which was published on the 21st of December, 2018. Here is a section, talking a particular port, that is wide open.

Major universities, state governments, and communications companies are among the organizations at risk of having their building-system data exposed, the
bureau said in an industry advisory obtained by CyberScoop. The port in question – port 1911 – is serving up building-network information on the internet
that could be of use to hackers.

“This default port discloses system information without authenticating, allowing cyber attackers to identify devices and systems that are not patched against
known exploits,” the FBI alert says. “Successful exploitation could lead to data leakage and possible privilege escalation.”

You’re welcome to check out this article in full, but I’ve never heard of this before. Is this the future of hacks? This can’t be good overall.