Should I be sending a post phone interview thank you email/letter?

My dad was saying that when he was applying for jobs (Probably 80s/90's?) that it was commonplace to be sending "thank you" emails / letters after a phone interview. Is this still the case? I feel like this is the old boomer way of thinking and really isn't commonplace or necessary at this point.

usa jobs
usa jobs resume
usa hotel jobs
usajobs
usa jobs federal government
usa job in ksa
usa jobs
usa jobs login
usa jobs gov
usajobs.gov
www.usajobs.gov
usajobs.com
usajobs
usajobs.gov official