Grandpa is unhappy. They're getting rid of the old-fashioned telephone, where you told the operator who you want to call, and replacing it with these durned fool dials! Dadgummed progress when things were running well enough without it. And they're doing away with the home telephone as it exists, the 'candlestick' phone, with a small earpiece, and replacing it with a blocky monstrosity. How is grandpa supposed to figure out how to use the thing?
Well, I grew up with the phone that grandpa feared, and it was easy: easier than grandpa's version, because he had to listen to make sure there was a dial tone, and by the time I was using the phone, twenty years or so after this film was released, you didn't have to listen for the dial tone. You could just start dialing, confident that there was a dial tone.
And that's progress. And so was using a dial to connect with whoever you were calling. Because what this short hints at but doesn't come out and say, is that if we needed an operator to put through every call, they would have had to hire a lot more people, and that would have made phone calls a lot more expensive.
So there, grandpa! That wasn't so hard, was it?