I don’t plan on zooming in.
If your camera catches someone that you don't know walking across your front lawn, you're almost guaranteed to find yourself zooming in on that recording to better see who it was.
Also, if you plan on watching your cameras remotely from a computer, smartphone or tablet, those screens often have more pixels than your current TV.
But like
@fenderman said, 4K cameras usually struggle in low light (like when it's dark outside) which is usually when most folks rely on the cameras the most. Because of that the most popular cameras on the forum here are the 2MP (and new 4MP) Dahua Starlight and Hikvision Dark Fighter models that were specifically designed for low light situations. The tech that Dahua/Hik use in their best low-light cameras is not available in consumer-grade models from companies like Lorex,
Amcrest, etc.
If you're interested in learning more, click on the
Wiki button (top blue bar) and look for the IP Cam
Cliff Notes item.