This is a really cool use of GPT, I love it! Anything that makes telemarketers and scammers waste their time and raises their costs/lowers their profitability is a good thing, in my view.
I like the idea of wasting telemarketing company resources, but we have to remember the people calling us are actual human being forced into shitty jobs where they suffer abusive management thanks to capitalism. So "torturing telemarketers" sounds bad to me, as does being rude to them or leaving them to talk into silence.
I usually pick up the phone, announce that I will hang up in 20 seconds, wish them a good day and then block the number.
I used to get 1-2 call per day, now it's more around 1 every 2 or 3 weeks.
I've been using https://jollyrogertelephone.com/ to do this for the past few years and it does seem to cut down on the overall # of spam calls I get. And even if that's just placebo effect, I still get dozens of funny recordings of telemarketers getting run around to laugh at.
Edit: it looks like they have started using AI recently, which can only make it better.