I spent the first portion of my career in production and I got pretty good at diagnosing and fixing production issues on gas wells. One thing I learned is that you can save yourself a lot of money and headache by identifying and fixing production issues early, before they grow and create downtime. The primary goal of every production team is to keep the wells flowing as much as possible. Measuring temperature at the wellhead is a very practical way to identify potential production issues downhole, such as salt or scale rings. These things don't form overnight and thus they can be really difficult to identify. If you have a gas well, temperature can be a really helpful diagnostic tool, because any flow restriction cause a temperature drop. If that restriction is downhole, then the temperature of the gas at surface will drop.
I am a big fan of measurement and if I was in charge of a production site I would have sensors everywhere. I would have sensors sensoring the sensors just to make sure the sensors don't stop sensoring. That's a little absurd but you get my point. Sensors provide data and data informs us of what's going on so that we can make educated decision quickly and accurately. I get that sensors cost money, but lost production costs a lot more.
A temperature sensor at the wellhead is a really practical way of identifying flow restriction downhole, quickly, so that you can get the well back to full production potential right away.
I'm not a production guy anymore, so I don't have a dog in the fight. But if I were, I'd have temperature sensors on my wellheads.