I would surmise that the object is to qualify you in a hurry so that the sales lead can be sold to a building contractor. There is no fast sale to someone who is not the "decision maker". If you have to "talk to the spouse" or whatever, the wage slave on the phone cannot proceed.
You have an opportunity to greet whomever arrives with audio and visual recording devices, preferably hidden, and gather the information needed to connect the illegal telemarketers to their clients. If successful you can plug your findings into a TCPA complaint and soak everyone involved for potentially thousands of dollars .... a more satisfying end to the story than a nip from a Rottie.
I get calls every day from this number....at least 3 a day. I just "receive" it and let it on until he/they get frustrated and hang up. I figure wasting their time with their waiting is a tiny payback. A voice keeps repeating "hello" until they get tired.