Pressure tank on public water

Any idea on why this would be installed on public supply? I’m assuming that this is a pressure tank and pump. Line on the bottom is the supply, top line goes out to the house lines.The property has a pool and sprinkler system but it didn’t seem to be connected to these. I tested the pressure on an outside bib and it was 52 psi. Ran water throughout the inspection and this did not run at all. Any thoughts? The gauge read 42 psi.

Some municipal water systems at the end of the line have less than 40 psi. Looks like this homeowner came up with his own solution.

Booster pump