What are the artistic reasons to shoot "Curb Your Enthusiasm" in a higher frame rate?
It gives me the impress I am watching an old show.
It looks like an old soap opera?
You're actually refering to a change in Frame Resolution not frame rate, increased frame rate is that horribly obnoxious thing they did with some versions of The Hobbit, made it look like a video game cut scene.
To answer your question though, the reason why they did changed from 480i to 1080i is simply because of the demand and pressure for it, with most other programs offering 1080i to their customers, to not do it would be to fall behind.
However, there might be a setting somewhere in your tv to adjust motion blur. Turn it down, that might help.