Having a listing in the yellow pages provides local exposure. You essentially pay for the traffic (leads).
Why have a .tel instead, that will get no traffic at all ? Doesn't make any sense to me.
Because .tels are able to replace phonenrs.
Sometimes you walk by a plumberoffice, he has a sign,
"plumber call 08-743 34 63"
(Sure he will be listed in the yellowpages but he can't advertise it)
Suddenly you need a plumber but can't remember his business name or phone nr you check the yellowpages and find another plumber. Good for you not for him.
Scenario 2.
Sometimes you walk by a plumberoffice, he has a sign,
"plumber NYplumber.tel"
Suddenly you need a plumber and this time you remember NYplumber.tel You write it in your cellphone and you call him, he gets a customer.
You are satisfied and next time you call him again you even recomend him. Its easy to share his phonenr.
A YP listing wont do that.
Sure he could have had NYplumber.com aswell but this plumber is no good at the internet and the NYplumber.com was 10 times more expensive and required a him to spend more time and money on a webpage. So the NYplumber.tel fits him better.
For him its the best solution.